Chemistry Test 144

Result

Chemistry Test 144

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
4 / -1

Directions For Questions

For an exothermic reaction, following two steps are involved.

Step 1. A + B → I (slow)

Step 2. I → AB (fast)

...view full instructions

Which of the following graphs correctly represent this reaction ?

A

B

C

D

Solution

In any reaction mechanism the no. of activated complexes showing maxima of potential energies is the no. of steps in that mechanism and in between these maxima is a valley where lies a more stable intermediate. There is one reaction intermediate lying at valley of two maxima representing two steps. E_a for first step should be higher than second step as first is slow step. These requirements fulfilled by choice (ii) & not choice (i) the choice (iv) is not possible because that is for endothermic reaction (Δ H + ve) & (ii) is single step equation so not possible.
Question 2
4 / -1

In which of the following arrangements, the sequence is not strictly according to the property written against it?

A
CO₂ < SiO₂ < SnO₂ < PbO₂ : increasing oxidising power

B
HF < HCl < HBr < HI : increasing acid strength

C
B < C < O < N : increasing first ionisation energy

D
NH₃ < PH₃ < AsH₃< SbH₃ : increasing basic strength

Solution

Drago's Rule :-

In case of NH₃, PH₃, - - - bond angle decrease ,NH₃ (≈107) & PH₃ (≈90) So, %S charactor of lp in NH₃ is less & %s charactor of lp top to bottom increase so basic charactor decrease.
Question 3
4 / -1

A crystal made up of particles X, Y, and Z. X forms fcc packing. Y occupies all octahedral voids of X and Z occupies all tetrahedral voids of X. It all particles along one body diagonal are removed, then the formula of the crystal would be

A
XYZ₂

B
X₂YZ₂

C
X₈Y₄Z₅

D
X₅Y₄Z₈

Solution

For fcc, number of X atoms = 4/unit cell

Number of Tetrahedral Voids = Z = 8

Number of Octahedral Voids = Y = 4

Number of atoms removed along one body diagonal = 2X (corner) and 2Z (TVs) and 1 Y (OV at body centre)

∴ Number of X atoms left = 4 - [2 × (1/8) ]= (15/4)

Number of Y atom left = 4 - (1 × 1) = 3

Number of Z atom left = 8 - (2 × 1) = 6

The simplest formula

⇒ X₅ Y₄Z₈
Question 4
4 / -1

In the formal charge on each oxygen atom and the P – O bond order are respectively

A
- 0.75, 0.5

B
- 3, 1.25

C
- 0.75, 1.0

D
- 0.75, 1.25

Solution

There are Four Resonating Structures B.O = 1.25
Question 5
4 / -1

Based on following information determine the value of x and y

atomic masses of Al,Cl and Ag are respectively 27,35.5,108.

A
x = 2, y = 3

B
x = 2, y = 2

C
x = 2, y = 1

D
x = 3, y = 4

Solution
Question 6
4 / -1

Aqueous ammonia is used as a precipitating reagent for Al³⁺ ions as Al(OH)₃ rather than aqueous NaOH, because

A
is a weak base

B
NaOH is a very strong base

C
NaOH forms [Al(OH)₄]^– ions

D
NaOH forms [ Al(OH)₂]⁺ ions.

Solution

Al(OH)₃ formed with NaOH dissolves in excess of NaOH to form aluminate ion.

which is stable.
Question 7
4 / -1

Bakelite is made from phenol and formaldehyde. The initial reaction between them is the example of :

A
Electrophilic aromatic substitution

B
Nucleophilic aromatic substitution

C
Free radical reaction

D
Aldol reaction

Solution

The reaction of phenol and formaldehyde, is called Lederer Mannase reaction. It follows electrophilic substitution and rearrangement reaction.
Question 8
4 / -1

An electron moving with velocity 'v' is found to have a certain value of de-Broglie wavelength. The velocity to be possessed by the neutron to have the same de-Broglie wavelength is

A
1840/v

B
1840 v

C
v/1840

D
v

Solution
Question 9
4 / -1

Chlorobenzene on heating with NaOH at 300^oC and high pressure followed by reaction with dil. HCl gives

A
Phenol

B
Benzaldehyde

C
Chlorophenol

D
None of these

Solution
Question 10
4 / -1

Directions For Questions

A sample of an ideal gas is expanded from original volume of 1m³ to twice its volume in a reversible process for which p = αV² (α = 5 atm m^{- 6})
Calculate

(i) Work done on P - V diagram

(ii) Calculate ΔS_m ifC _V_m = 20J K ^-1m -1 , R = 8JK^–1 m^–1 and ln2 = 0.7

...view full instructions

The values of work done & ΔS_m may be

A

B

C

D

Solution