Question 1 1.25 / -0
A piece of paper in the shape of a sector of a circle (see figure 1) is rolled up to form a right circular cone (see figure 2). The value of the angle
is
Solution
Radius of the circle =
= 13
Area of the surface of a circle in figure 1 =
=
.......(i)
Area of the curved surface of cone in figure 2 =
=
....... (ii)
From equations (i) and (ii), we get
Question 2 1.25 / -0
The number of pairs of real (x, y) such that x = x2 + y2 and y = 2xy is
Solution
x = x
2 + y
2 .... (1)
Since y = 2xy, so x =
Put the value of 'x' in equation (1), we get
=
+ y
2 y
2 =
, so y =
So, solutions are
and
.
Hence, the total number of solutions = 2.
Question 3 1.25 / -0
In a right triangle ABC, the incircle touches the hypotenuse AC at D. If AD = 10 and DC = 3, the inradius of ABC is
Solution
(r + 3)
2 + (r + 10)
2 = (13)
2 ⇒ r
2 + 9 + 6r + r
2 + 100 + 20r = 169
⇒ 2r
2 + 26r - 60 = 0
⇒ r
2 + 13r - 30 = 0
⇒ (r + 15) (r - 2) = 0
⇒ r = 2
Question 4 1.25 / -0
A man covered a certain distance by train at the rate of 25 kmph and walked back at the rate of 4 kmph. The whole journey took 5 hours 48 minutes. What is the total distance covered by him?
Solution
Let the total distance be '2x' km.
Then,
+
= 5
= 5
=
=
x = 20 km
Hence, total distance = 2x = 20 + 20 = 40 km
Question 5 1.25 / -0
If a + b + c = 6 and
, then find
Question 6 1.25 / -0
A woman has 10 keys out of which only one opens a lock. She tries the keys one after the other (keeping aside the failed ones) till she succeeds in opening the lock. What is the chance that it is the seventh key that works?
Solution
If the 7
th key is correct, then all the first six are incorrect.
So, we want: no - no - no - no - no - no - yes
The probabilty =
=
Hence, the chance that its the 7
th key that works =
.
Question 7 1.25 / -0
The area of a circle is 154 cm2 . If the radius gets doubled, what will be the new area?
Solution
Area = 154 cm
Area =
154 =
= r
2 r
2 = 49
r = 7
New r = 2
7 = 14 cm
Area =
=
= 22
2
14
= 616 cm
2
Question 8 1.25 / -0
The lengths of the sides of a right-angled triangle are in the ratio 3 : 4. The area of the triangle is 726 square units. The length of the hypotenuse (in proper units) is
Solution
Area of the triangle =
× base × height =
× 3x × 4x = 726
Solving, x = 11
Thus, length of hypotenuse = 5x = 5 × 11 = 55 units
Question 9 1.25 / -0
The number of positive integers n in the set {1, 2, 3, ..., 100}, for which the number
is an integer, is
Solution
We know,
1
2 + 2
2 + 3
2 + 4
2 + ... + n
2 =
and
1 + 2 + 3 +... + n =
Then,
=
=
So, the numbers for which the value of this expression is an integer are 1, 4, 7, ..., 100.
Hence, total number of values = 34.
Question 10 1.25 / -0
A cow is tied to a corner (vertex) of a regular hexagonal fenced area of side a metres by a rope of length 5a/2 metres in a grass field. The cow cannot graze inside the fenced area. What is the maximum possible area of the grass field to which the cow has access to graze?
Solution
Area of the regular hexagon =
Total surface area formed by circle on the grass field =
=
a
2 Hence, maximum possible area of the grass field to which the cow has access to graze =
=
Question 11 1.25 / -0
'A' can construct a wall in 30 days, whereas 'B' can construct or destroy the same wall in the same time i.e. destroy time is equal to construct time. If 'A' constructs and 'B' destroys, it takes 60 days to construct the wall. How many days will it take to construct the wall, if both 'A' and 'B' work towards constructing the wall?
Solution
Let us assume that 'B' can destroy the wall in 'd' days.
⇒ d = 60 days
So, if both 'A' and 'B' work to construct the wall,
In 1 day, they can do
So, it takes 20 days to construct the wall, if both 'A' and 'B' work towards constructing the wall.
Question 12 1.25 / -0
In a triangle, three lines are drawn so that each line connects the mid-point on one side with any point on an adjacent side. What is the greatest number of over-lapping regions in the triangle that can be formed by the sides and the three lines?
Solution
In the diagram, one line makes two regions, no matter how you draw. Two lines add two regions for a total of four regions. So, the pattern seems to be:
1
2
2
4
3
7
where each L
th line adds L regions to whatever regions already existed.
Thus, three lines make 7 regions.
Question 13 1.25 / -0
Rohan sleeps at 10 pm and wakes up at 7 am. He bathes from 7 am to 8 am. He plays from 8 am to 10 am and again from 5 pm to 8 pm. He takes his dinner from 8 pm to 9 pm and watches TV from 9 pm to 10 pm and he studies the rest of the time. Which of the following represents his study time in fractions?
Solution
Rohan sleeps for 9 hours;
bathes for 1 hour;
plays for 5 hours;
has dinner for 1 hour;
watches TV for 1 hour;
So, the rest of the time that is for studying = 24 – (9 + 1 + 5 + 1 + 1) = 7 hours
So, the fraction for his study time =
.
Question 14 1.25 / -0
A rectangle is divided into 16 sub-rectangles as shown in the figure. The number in each sub-rectangle represents the area of that sub-rectangle. What is the area of the rectangle KLMN?
Solution
xy = 10 and yz = 4 then z =
x =
x
and
a = 12 ⇒ a
, therefore
× b = 15 ⇒ b
× C = 25 ⇒ C =
Hence, area of rectangle KLMN = x ×
= 50.
Question 15 1.25 / -0
If the sides of a triangle are 13 units, 14 units, and 15 units, then the radius of its in-circle is
Solution
In-radius =
Δ =
Semi perimeter s =
units
So, Δ =
=
= 4 × 3 × 7 = 84 units
Hence, r =
= 4 units
Question 16 1.25 / -0
Two immiscible liquids, A and B are kept in a U-tube. If the density of liquid A is smaller than the density of liquid B, then the equilibrium situation is
Solution
Pressure on horizontal line (at the interface of liquids A and B) is same in both the columns.
We know that,
As liquid A has less density than liquid B, so small amount (height) of liquid B can balance the large amount of liquid A.
Question 17 1.25 / -0
We are able to squeeze snow and make balls out of it because of
Solution
We are able to squeeze snow and make balls out of it due to water's unusual behaviour.
Question 18 1.25 / -0
Consider the circuit below. The bulb will light up if
Solution
If S3 will be closed, then bulb will never light up because current will flow through S3 , because S3 will offer resistance-free path. Now for completion of circuit, atleast one from S1 and S2 should be closed.
Question 19 1.25 / -0
A soldier with a machine gun, falling from an airplane gets detached from his parachute. He is able to resist the downward acceleration if he shoots 40 bullets a second at the speed of 500 m/s. If the weight of a bullet is 49 gm, what is the weight of the man with the gun? Ignore resistance due to air and assume the acceleration due to gravity g = 9.8 ms-2 .
Solution
Let the mass of the soldier be M.
⇒ Mg = (49/1000) × 40 × 500 (because to resist the acceleration, force should be equal in both directions)
⇒ M =
= 100 kg
Question 20 1.25 / -0
A bus and a car start from rest and run along a straight road with uniform acceleration of 2 m/s2 and 3 m/s2 respectively, with the car behind the bus at a distance of 1 m. How long will it take for both the bus and car travel side by side?
Solution
Using the concept of relative motion, we have
Where s
cb is the relative displacement of car with respect to bus, u
cb is the initial relative velocity of car with respect to bus a
cb is the relative acceleration of car with respect to bus.
u
bc = 0, a
cb = 3 - 2 = 1 m/s
2 & s
cb = 1 m
or t = 1. 4 sec
Question 21 1.25 / -0
Twelve positive charges of magnitude q are placed on a circle of radius R in a manner that they are equally spaced. A charge +Q is placed at the centre. If one of the charges q is removed, then the force on Q is
Solution
Due to the symmetry, net force on Q was zero initially.
After removing one 'q' charge,
Force due to removed q charge on Q| = |Force due to left 11 q charges on Q|
So, force acting on Q =
towards the position of the removed charge.
Question 22 1.25 / -0
An electric heater consists of a nichrome coil and runs under 220 V, consuming 1 kW power. Part of its coil burns out and it is reconnected after cutting off the burnt portion. The power it will consume now is
Solution
We know, P = (V2 /R)
Question 23 1.25 / -0
A ray of light passes through an equilateral prism such that an angle of incidence is equal to the angle of emergence, and the latter is equal to
th the angle of prism. The angle of deviation is
Solution
Angle of incidence = angle of emergence,
ie, i = i'
Also, i' =
× angle of equilateral prism
=
× 60° = 45°
Thus, angle of deviation δ
= i + i' - A
δ = (45° + 45° - 60°) = 30°
Question 24 1.25 / -0
What is the resistance between point A and C?
Solution
Resistance R
2 and R
3 between B and C are in parallel, hence equivalent resistance between B and C is:
This equivalent resistance is in series with R
1 , hence equivalent resistance between A and C is:
Question 25 1.25 / -0
When a fuse is rated 8 A, it means it
Solution
A fuse protects a circuit from excess current. It will melt if the current exceeds 8 A.
Question 26 1.25 / -0
A symmetric double convex lens is cut into two equal parts by a plane perpendicular to the principal axis. If the power of original lens is 4D, the power of a cut lens will be
Solution
Power of lens is divided when a symmetric double convex lens is cut into two equal parts by a plane perpendicular to the principal axis. So, power of a cut lens =
= 2D
Question 27 1.25 / -0
A juggler tosses a ball up in the air with initial speed 'u'. At the instant it reaches its maximum height H, he tosses up a second ball with the same initial speed. The two balls will meet at
Solution
Let both balls meet at point C after time 't' when the second ball is thrown.
For the first ball, we have
----- (1)
For the second ball, we have
----- (2)
From (1) and (2), we get
---- (3)
As the first ball reaches the maximum height H, then using
---- (4)
From (3) and (4), we get
---- (5)
From (1) and (5), we get
Question 28 1.25 / -0
On a horizontal frictionless frozen lake, a girl (36 kg) and a box (9 kg) are connected to each other by means of a rope. Initially they are 20 m apart. The girl exerts a horizontal force on the box, pulling it towards her. How far has the girl travelled when she touches the box?
Question 29 1.25 / -0
The principle used for the transmission of light signals through the optical fibre is
Solution
The optical fibre consists of three parts
(i) Central core made of glass or plastic.
(ii) Central core is surrounded by cladding, a material of refractive index less than that of central core.
(iii) Cladding is surrounded by an insulating jacket called protective jack.
When light enters the central core and incident on the interface of central core and cladding at an angle greater than critical angle, total internal reflection takes place. This process is repeated again and again and light propagates through optical fibre.
Therefore the transmission of light signals through the optical fibre is based on the principle of total internal reflection.
Question 30 1.25 / -0
A convex lens is used to form an image of an object on a screen. If the upper half of the lens is blackened so that it becomes opaque, then
Solution
A convex lens is used to form an image of an object on a screen. If the upper half of the lens is blackened so that it becomes opaque, then the image will be formed with reduced brightness as light reaching from each and every part of the object through lens, with blackened part, will be less as the aperture of the lens is reduced.
Question 31 1.25 / -0
The molecular formula of marsh gas is ________.
Solution
The molecular formula of marsh gas is: CH4 .
Question 32 1.25 / -0
The correct order of increasing basic nature for bases NH3 , CH3 NH2 , (CH3 )2 NH is
Solution
Basic character of amines increases with increase in the electron density on the nitrogen atom.
Question 33 1.25 / -0
The type of hybridisation in CH2 = CH2 is
Solution
Both carbon atoms in ethylene are sp2 hybridised.
Question 34 1.25 / -0
Which of the following will have the highest second ionisation energy from the ground state of electronic configuration of various electrons?
Solution
1s2 , 2s2 , 2p6 , 3s1 represents the configuration of sodium. After losing one electron, it acquires the stable electronic configuration of neon. Hence, the second ionisation energy will be exceptionally high.
Question 35 1.25 / -0
Two isotonic nuclides X and Y have mass numbers 35 and 37 respectively. If the atomic number of X is 17, the atomic number of Y will be _______.
Solution
Nuclides having the same number of neutrons, but different number of protons are said to be isotonic.
Question 36 1.25 / -0
Which of the following is a polar compound?
Solution
Because of large electronegativity difference between hydrogen and chlorine, the H-Cl bond is a polar bond and HCl is a polar molecule.
Question 37 1.25 / -0
What will be the number of molecules present in 16 g of O2 ?
Solution
1 gm of O
2 =
molecules
16 gm of O
2 =
molecules 16 gm of O
2 = 3.011 × 10
23 molecules
Question 38 1.25 / -0
The helical structure of proteins is stabilized by
Solution
An alpha helix is secondary structure of proteins. The stability of such structures is primarily provided by hydrogen bonding between 'hydrogen' of amino group of amino acid and 'oxygen' of carbonyl group of another amino acid.
Question 39 1.25 / -0
A solution is highly acidic in nature and a small quantity of a weakly basic solution is added to it. What will be the chemical nature of the resulting solution?
Solution
When a highly acidic solution is mixed with a small quantity of a weakly basic solution, the hydroxide (OH- ) ions from the base will combine with the H+ ions of acid and neutralise it. However, the number of OH- ions per unit volume in a weak base will be very less as compared to that of H+ ions in a strong acid. Therefore, the neutralisation will not be complete and the resultant solution will remain acidic.
Question 40 1.25 / -0
In the reaction PCl
5 (g)
PCl
3 (g) + Cl
2 (g), the equilibrium concentrations of PCl
5 and PCl
3 are 0.4 and 0.2 mole/litre, respectively. If the value of K
C is 0.5, then what is the concentration of Cl
2 in mole/litre?
Question 41 1.25 / -0
In which of the following compounds does nitrogen have an oxidation state of − 1?
Solution
Nitrogen has an oxidation state of + 1 in N2 O.2 - .2 OH.2 H4 .
Question 42 1.25 / -0
Non-metals are poor conductors of electricity because of the absence of
Solution
A non-metal atom has 4, 5, 6, 7 or 8 electrons in its valence shell. These electrons are not free. That is why non-metals do not conduct electric current. Protons and neutrons, which are present in the nucleus of every atom, have no role in the conduction of electricity.
Question 43 1.25 / -0
Which of the following compounds is not a hydrocarbon?
Solution
Phenol is not a hydrocarbon, it is C6 H5 OH. Hydrocarbons are compounds containing only carbon and hydrogen.
Question 44 1.25 / -0
Which of the following word equations is incorrect?
Solution
Iron is less reactive than zinc. So, it will not be able to displace zinc from zinc sulphate. Therefore, reaction (1) is incorrect.
Question 45 1.25 / -0
The correct increasing order of energies of atomic orbitals is
Solution
The correct increasing order of energies of atomic orbitals is
By Aufbau's principle the orbitals get filled in the increasing order of their n + l values.
For the same n + l value the orbital with a lower value of n gets filled first.
5p: 5 + 1 = 6
6s: 6 + 0 = 6
4f: 4 + 3 = 7
5d: 5 + 2 = 7
Question 46 1.25 / -0
Vitamin excreted by urine in higher vertebrates is
Solution
Vitamin C is water soluble vitamin. Other options are fat soluble vitamins. So, vitamin C is excreted in urine.
Question 47 1.25 / -0
Which of the following is related to the central nervous system?
Solution
The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord
Question 48 1.25 / -0
Identify the group among the following, which contains all the viral diseases.
Solution
Influenza, mumps and dengue fever are caused by viruses.
Question 49 1.25 / -0
If tall height (TT) is a dominant trait and short height is a recessive trait (tt) in the garden pea, then which of the following statements is true?
Solution
(T) is dominant, while (t) is recessive. It means that when (T) and (t) are present together, the effect of (T) will hide the effect of (t). But in the absence of (T), the effect of (t) will be visible. Thus, (TT) are tall, while (tt) are short. But in (Tt), the tall feature dominates short-height trait. So, only (2) is correct.
Question 50 1.25 / -0
Fucus, an alga has which of the following types of life cycle?
Solution
Fucus, an alga is diplontic.
Question 51 1.25 / -0
Bidder's canal is found in
Solution
Bidder's canal is found in kidney of frog.
Question 52 1.25 / -0
Klinefelter's syndrome in humans is an archetype of chromosomal aneuploidy. It is diagnosed by
Solution
A karyotype is used to show the number, types and appearance of chromosomes. Therefore, an extra X chromosome in a Klinefelter's person could be readily diagnosed by karyotyping.
Question 53 1.25 / -0
At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell?
Solution
G2 phase is a period of rapid cell growth and protein synthesis during which the cell readies itself for mitosis. So, during G–2 stage of interphase histone proteins synthesized in a eukaryotic cell.
Question 54 1.25 / -0
Which of the following cell types is considered as cell fragment and not a complete cell?
Solution
Platelets are irregular cell fragments that occur in blood. They are derived from fragmentation of large megacaryocytes.
Question 55 1.25 / -0
The fusion of sperm and egg initially results in formation of
Solution
Gametes – These are the germ cells capable of growing. For example,
Gametes fuse to form a zygote.
Embryo – Zygote divides several times to form an embryo.
Fetus – It is a developing mammal or other viviparous (which gives birth to young ones) vertebrate, after the embryonic stage and before the birth.
Question 56 1.25 / -0
In meiosis, germ cells will undergo two successive divisions in which
Solution
Meiosis comprises two successive nuclear divisions with only one round of DNA replication produce four haploid cells.
Question 57 1.25 / -0
The enzymes which differ slightly in structure, but can catalyze the same type of reaction, are known as
Solution
Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters, or are regulated differently. They permit the fine-tuning of metabolism to meet the particular needs of a given tissue or developmental stage.
Question 58 1.25 / -0
Where do endocrine glands release their secretions?
Solution
Endocrine glands release their secretions directly into the blood stream. They let out the produced hormones by way of the blood vessels supplying the glands.
Question 59 1.25 / -0
Which of the following is the feature of skeletal muscle fibres?
Solution
Skeletal muscle fibres are cylindrical shaped with blunt ends. They have characteristic dark and light bands which give them a striated appearance. They are multinucleated and have numerous mitochondria as they have to produce a lot of energy.
Question 60 1.25 / -0
Sacculated, fusiform or cylindrical forms are the main forms of which of the following diseases?
Solution
Aneurysm is the enlargement of an artery caused by weakness in the arterial wall. Aneurysms often occur in the aorta, brain, back of the knee, intestine or spleen. A ruptured aneurysm can result in internal bleeding and stroke. Sacculated, fusiform or cylindrical forms are the main forms of aneurysm.
Question 61 1.25 / -0
Solve the following system of inequalities:
(A) 3x - 4 < 8x + 6
(B) 2x - 1 > 5x - 4
(C) 11x - 9
15x + 3
Solution
(A) gives 3x - 8x < 6 + 4 or -5x < 10 or x > -2.
(B) gives 2x - 1 > 5x - 4 or -3x > -3 or x < 1.
(C) gives 11x - 9
15x + 3 or -4x
12 or x
-3.
The three results can be displayed as follows:
The intersection of the three is -2 < x < 1.
Question 62 1.25 / -0
Two vertices of a triangle are (– 2, 3) and (5, – 1). Its orthocentre lies at the origin and centroid lies on the line x + y = 7. Then the third vertex lies at
Solution
Let O(0, 0) be the orthocentre; A(h, k) the third vertex; and B(-2, 3) and C(5, -1) the other two vertices.
Then the slope of the line through A and O is k/h, while the line through B and C has the slope - 4/7.
By the property of the orthocentre, these two lines must be perpendicular,
so we have
= -1 ⇒
...(i)
Also
= 7
⇒ h + k = 16 ...(ii)
Which is not satisfied by the points given in (a), (b) or (c).
Question 63 1.25 / -0
In the figure below, ΔAOB is an equilateral triangle. What is
CAB?
Solution
A +
OAB +
BAC = 180°
90° + 60° +
BAC = 180°
BAC = 30°
ABO +
ABC = 180°
ABC = 180°
- 60° = 120°
In
ABC
CAB = 180 -
BAC -
ABC
= 180° - 30° - 120°
= 30°
Question 64 1.25 / -0
A rectangle having dimensions x
y has a unit square placed in the bottom right corner. Diagonal of length d, joining the bottom left corner with the top right corner of the rectangle, passes through the vertex of the square. If the area of the rectangle is an integer, then which one of the following is a possible value of d
2 + 1?
Solution
By Pythagoras theorem, x
2 + y
2 = d
2 ... (i)
By similar triangles,
.
(x − 1)(y − 1) = 1
xy − x − y + 1 = 1
xy = x + y
Squaring both sides, we get: (xy)
2 = x
2 + y
2 + 2(xy) = d
2 + 2(xy) [From (i)]
(xy)
2 − 2(xy) = d
2 (xy)
2 − 2(xy) + 1 = d
2 + 1
(xy − 1)
2 = d
2 + 1
xy − 1 = ±√(d
2 + 1)
xy = 1 ± √(d
2 + 1)
But as the area xy > 0, we only need to take the positive root.
xy = 1 + √(d
2 + 1)
So, for xy to be an integer, d
2 + 1 must be a perfect square, which is satisfied by option (2), i.e. 36.
Question 65 1.25 / -0
In a triangle ABC, AB = AC = 37. Let D be a point on BC such that BD = 7, AD = 33. The length of CD is
Solution
Suppose in the given triangle, AE is an altitude on BC.
Let distance DE = y, length AE = z
Using Pythagoras theorem in
ABE, we get
(37)
2 = (7 + x)
2 + z
2 ...... (i)
In
ADE,
(33)
2 = x
2 + z
2 ......(ii)
So, from equations (i) and (ii), we get
(37)
2 - (7 + x)
2 = (33)
2 - x
2 14x + 49 = 1369 - 1089
14x = 280 - 49
x = 16.5
and from equation (i), Z =
Using Pythagoras theorem in
AEC, we get
(37)
2 =
+ (EC)
2 (EC)
2 = 1369 - 816.75 = 552.25
EC = 23.5
Hence, length DC = DE + EC = 16.5 + 23.5 = 40
Question 66 1.25 / -0
The same force acts on two bodies of different masses 3 kg and 5 kg initially at rest. The ratio of times required to acquire the same final velocity is
Solution
From Newton's second law
F =
⇒ t =
⇒
Given, m
1 = 3 kg, m
2 = 5 kg
∴
Question 67 1.25 / -0
According to the quantum theory, a photon of electromagnetic radiation of frequency
has energy E = h
, where 'h' is known as Planck`s constant. According to the theory of relativity, a particle of mass 'm' has equivalent energy E = mc
2 , where 'c' is the speed of light. Thus, a photon can be treated as a particle having effective mass m =
. If a flash of light is sent horizontally in the earth's gravitational field, then photons while travelling a horizontal distance 'd' would fall through a distance given by
Solution
Correct Answer: 1
In horizontal direction, velocity V
H = c
Horizontal distance = d
So, time taken to travel distance d is t = d/c
Vertical downward initial velocity is zero.
After time t = d/c, distance covered vertically is
H = ut + (1/2)at
2 H = 0 + (1/2)g(d/c)
2 H =
Question 68 1.25 / -0
The current I in the given circuit is
Solution
Here, two resistances
and
are in series.
Equivalent resistance =
This equivalent resistance is in parallel with
.
Resistance of the circuit:
Using Ohm's law, V = IR
Question 69 1.25 / -0
The magnifying power of objective of a compound microscope is 5. If the magnifying power of microscope is 30, then the magnifying power of eyepiece will be
Solution
Total magnification is
M = M
o × M
e Given, M = 30, M
o = 5
⇒ M
e =
= 6
Question 70 1.25 / -0
Two identical spheres carrying charges - 9 µC and 5 µC, respectively are kept in contact and then separated from each other. Choose the correct option which completes the following sentence.
Solution
Charge on first sphere q
1 = - 9µC
Charge on second sphere q
2 = 5µC
Charge on each sphere after they are kept in contact
=
=
-2µC
If n electrons are in excess on each sphere then
n =
=
= 1.25 × 10
13 Therefore, 1.25 × 10
13 electrons are in excess on each sphere.
Question 71 1.25 / -0
Directions: + ions (Eo RP = – 2.36V) is
Solution
E = E°
RP +
log [M
+ ]
Given, E°
RP = -2.36 V, [M
+ ] = 0.1 M
n = 1 (for M
+ M)
E = E°
RP +
log [M
+ ]
= -2.36 +
log 0.1
= -2.36 + 0.0591 × (-1)
= -2.36 - 0.0591
= -2.419 V
Question 72 1.25 / -0
Directions: 5 H10 Cl2 . It, on hydrolysis, gives C5 H10 O, which reacts with NH2 OH to form iodoform, but does not give Fehling test. 'A' is
Solution
(i)
C
5 H
10 O must be aldehyde or ketone because it reacts with NH
2 OH.
(ii) It must be aldehyde as it does not give Fehling test.
(iii) It must have CH
3 CO group becasue it gives iodoform test.
Question 73 1.25 / -0
How many stereoisomers is shown by a glucose molecule having 4-asymmetric carbonation?
Solution
24 = 16 stereoisomers are possible for glucose molecule.
Question 74 1.25 / -0
An organic compound containing carbon, hydrogen and oxygen contains 52.20% carbon and 13.04% hydrogen. Vapour density of the compound is 23 g/m3 . Its molecular formula will be
Solution
Element Percentage Mol. wt. Relative ratio Simple ratio C 52.20 12 H 13.04 1 O 34.76 16
Empirical formula = C
2 H
6 O
1 Empirical formula weight
= 2 × 12 + 1 × 6 + 16
= 24 + 6 + 16
= 46
n =
= 1
Molecular weight = 2 × vapour density
= 2 × 23 = 46
Molecular formula = n (Empirical formula)
= 1(C
2 H
6 O)
= C
2 H
6 O
Question 75 1.25 / -0
For the reaction: H2 (g) + I2 (g) ⇌ 2HI(g), the equilibrium constants expressed in terms of concentration Kc and partial pressure Kp are related as
Solution
For the reaction2 (g) + I2 (g) ⇌ 2HI(g)p = Kc (RT)Δn p = Kc p and Kc are equilibrium constants in terms of partial pressures and concentrations.)
Question 76 1.25 / -0
Portuguese man o' war or physalia is a
Solution
Portuguese man o' war or physalia is a polymorphic coelentrate.
Question 77 1.25 / -0
In a cross between red-eyed female dragonfly and a white-eyed male dragonfly what percent of the male progenies will have white eyes? (White eyes are X-linked recessive)
Solution
The pure breed female is homozygous with the normal X chromosome and the white-eyed male is hemizygous for the X chromosome with a white eye mutation. Therefore, all male and female progenies are red-eyed.
Question 78 1.25 / -0
Mechanical support, enzyme circulation and protein synthesis are the main functions of
Solution
All listed functions are concerned with ER.
Question 79 1.25 / -0
According to widely accepted "fluid mosaic model" cell membranes are semi–fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?
Solution
Most large proteins do not flip-flop due to their extensive polar regions, which are unfavorable in the hydrophobic core of a membrane bilayer. This allows the asymmetry of membranes to be retained for long periods, which is an important aspect of cell regulation.
Question 80 1.25 / -0
Organisation of stem apex into corpus and tunica is determined mainly by
Solution
The tunica corpus concept was given by Schmidt (1924) which was based on plane of divisions of cells. According to this concept there are two portions in shoot apex : tunica and corpus. The tunica shows only anticlinical divisions and thus it is responsible for surface growth. The corpus shows divisions in all plane and thus responsible for volume growth.
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