Chemistry Test

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Chemistry Test - 37

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following polymers has ester linkage?

A
Nylon

B
Bakelite

C
Terylene

D
PVC

Solution

Terylene or dacron is formed from ethylene glycol and terephthalic acid. It has ester linkages as shown in the figure.
Hence, the correct option is (C)
Question 2
1 / -0

Cation having maximum number of unpaired electrons is _____________.

A
Mn⁺²

B
Fe⁺²

C
Co⁺²

D
Ni⁺²

Solution

Mn⁺² is a cation of magnesium which contain 5 unpaired electron.
Hence, the correct option is (A)
Question 3
1 / -0

The correct statement regarding entropy is:

A
at absolute zero temperature, entropy of a perfectly crystalline solid in zero.

B
at absolute zero temperature, the entropy of a perfectly crystalline substance is ++ve.

C
at absolute zero temperature, the entropy of all crystalline substances is zero.

D
at 0^oC, the entropy of a perfect crystalline solid is zero.

Solution

The correct statement regarding entropy is represented by the option (A).

At absolute zero temperature, entropy of a perfectly crystalline solid in zero. This is according to the third law of thermodynamics.

At absolute zero, the perfect crystal has only one minimum energy state.
Hence, the correct option is (A)
Question 4
1 / -0

X(s)⇌A(g)+2B(g)

Y(s)⇌2B(g)+C(g)

KP1=9×10⁻³atm³

If the ratio, K_P1: K_P2=2, then the total pressure of gases over a mixture of excess of X and Y is :

A
4.5 atm

B
0.45 atm

C
0.6 atm

D
none of these

Solution

Let, the partial pressures of A and B from X are x atm and 2x atm respectively. \(K_{P_{1}}=9 \times 10^{-3} a t m^{3}=x(2 x)^{2}=4 x^{3}\)
\(x=0.131 a t m\)
The total pressure is \(x+2 x=3 x=3(0.131)=0.393\) atm.
Let, the partial pressure of \(\mathrm{C}\) is \(\mathrm{y}\) atm. \(K_{P_{2}}=0.5 \times 9 \times 10^{-3} \mathrm{atm}^{3}=4.5 \times 10^{-3} \mathrm{atm}^{3}=y(0.262)^{2}\)
\(y=0.0655\)
Total pressure of gases from \(\mathrm{X}\) and \(\mathrm{Y}\) is \(0.393+0.00655=0.45 \mathrm{atm}\)
Hence, the correct option is (B)
Question 5
1 / -0

The monomer of nylon-6 is :

A
cyclohexane

B
caprolactam

C
ethylene glycol

D
amino acid

Solution

Hence, the correct option is (B)
Question 6
1 / -0

Zn Amalgam is prepared by the electrolysis of aqueous ZnCl₂ using Hg cathode (9 gm). How much current should be passed through ZnCl₂ solution for 1000 seconds to prepare a Zn amalgam with 25% Zn by weight ?(Zn atomic weight =65.4)

A
5.6 A

B
7.2 A

C
8.85 A

D
11.2 A

Solution

First calculate the quantity of zinc required. Let \(x\) be the total mass of amalgam.
Mass of mercury \(=0.75 x=9 g \Longrightarrow x=12 g\)
Mass of zinc \(=0.25 x=0.25 \times 12 g=3 \mathrm{g}\)
Quantity of electricity passed \(=Q(C)=I(A) \times t(s)=I(A) \times 1000 s\) The atomic weight of zinc is \(65.4 \frac{g}{m o l}\) Moles of electrons passed \(=\frac{Q(C)}{96500 \frac{C}{\text { mol } e^{-}}}=\frac{I(A) \times 1000 s}{96500 \frac{C}{\text { mol } e^{-}}}\)
The weight of zinc deposited, \(3 g=\) molar mass of zinc \(\times\) mole ratio \(\times\) moles of electrons passed
\(3 g=65.4 \frac{g}{m o l} \times \frac{1 \text { mol zinc }}{2 \text { mol } e^{-}} \times \frac{I(A) \times 1000 s}{96500 \frac{C}{\text { mol } e^{-}}}\)
\(I(A)=8.85 A\)
Hence, the correct option is (C)
Question 7
1 / -0

In an atom, two electrons move around the nucleus in circular orbits of radii R and 4R. The ratio of the time taken by them to complete one revolution is (consider Bohr model to be valid):

A
1:4

B
4:1

C
1:8

D
8:7

Solution

\(T^{2} \propto n^{6}\)
\(T^{2} \propto r^{3}\)
\(T \propto r^{3 / 2}\)
\(\frac{T_{1}}{T_{2}}=\left(\frac{r_{1}}{r_{2}}\right)^{\frac{3}{2}}=\left(\frac{R}{4 R}\right)^{\frac{3}{2}}=\frac{1}{8}\)
Hence, the correct option is (C)
Question 8
1 / -0

The solubility of Pb(OH)₂ in water is 6.7×10⁻⁶M. Calculate the solubility of Pb(OH)₂ in a buffer solution of pH=8.

A
1.0×10⁻²M

B
1.3×10⁻⁵M

C
1.2×10⁻³M

D
2.1×10⁻³M

Solution

The solubility of \(P b(O H)_{2}\) in water is \(6.7 \times 10^{6} \mathrm{M}\) Thus, \(\left[P b^{2+}\right]=6.710^{6} \mathrm{M}\) and \(\left[O H^{-}\right] 2 \times\left(6.710^{6}\right)=1.3410^{5}\)
The expression for the solubility product is \(K_{s p}=\left[P b^{2+}\right]\left[O H^{-}\right]^{2}\) Substitute values in the above expression. \(K_{s p}=\left(6.710^{6}\right) \times\left(1.3410^{5}\right)^{2}=1.2 \times 10^{-15}\)
In buffer solution of pH \(8, p O H=14-8=6\) or \(\left[O H^{-}\right]=10^{-6}\) Substitute values in the expression for the solubility product. \(1.2 \times 10^{-15}=\left[P b^{2+}\right]\left(10^{-6}\right)^{2}\)
\(\left[P b^{2+}\right]=1.2 \times 10^{-3} \mathrm{M}\)
Hence, the correct option is (C)
Question 9
1 / -0

Which of the following is a polysacchardie?

A
Starch

B
Maltose

C
Lactose

D
Arabinose

Solution

Starch is a polysacchardie. In it, thousands of monosacchardie units are joined by glycosidic linkages. Maltose and lactose are disaccharides. Arabinose is a monosaccharide.
Hence, the correct option is (A)
Question 10
1 / -0

Granite is polished by :

A
carborundum

B
quartz

C
silicones

D
topaz

Solution

Granite is a premium building material that stands out for its long-lasting beauty. Slabs of granite are polished by special machines that use either large metal discs or abrasive bricks made from silicon carbide. The polishing process produces a sparkling gloss and a finish as smooth as glass.
Hence, the correct option is (A)

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Chemistry Test - 37

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Chemistry Test - 37

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SHARING IS CARING

Question 1

Nylon

Bakelite

Terylene

PVC

Solution

Question 2

Mn+2

Fe+2

Co+2

Ni+2

Solution

Question 3

at absolute zero temperature, entropy of a perfectly crystalline solid in zero.

at absolute zero temperature, the entropy of a perfectly crystalline substance is ++ve.

at absolute zero temperature, the entropy of all crystalline substances is zero.

at 0oC, the entropy of a perfect crystalline solid is zero.

Solution

Question 4

4.5 atm

0.45 atm

0.6 atm

none of these

Solution

Question 5

cyclohexane

caprolactam

ethylene glycol

amino acid

Solution

Question 6

5.6 A

7.2 A

8.85 A

11.2 A

Solution

Question 7

1:4

4:1

1:8

8:7

Solution

Question 8

1.0×10−2M

1.3×10−5M

1.2×10−3M

2.1×10−3M

Solution

Question 9

Starch

Maltose

Lactose

Arabinose

Solution

Question 10

carborundum

quartz

silicones

topaz

Solution

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Mn⁺²

Fe⁺²

Co⁺²

Ni⁺²

at 0^oC, the entropy of a perfect crystalline solid is zero.

1.0×10⁻²M

1.3×10⁻⁵M

1.2×10⁻³M

2.1×10⁻³M