# Chemistry (2017) | Study Mode

Question 31
A

fused CaO

B

H2O

C

NaOH

D

Concentrated H2SO4

##### Explanation
In the preparation of sulphur dioxide by the action of dilute acids on sulphates and bisulphites. conc H2SO4 helps to release SO2 from the mixture.
The setup represents the production of sulphur dioxide

Question 32
A
0.300g
B
0.250g
C
0.2242g
D
0.448g
##### Explanation
M = $$\frac{\text{Molar mass x Quantity of Electricity}}{\text{96500 x no of charge}}$$

= $$\frac{MmIT}{96500n}$$

Copper II Chloride = CuCl2

CuCl2 ? Cu2+ + 2Cl2

Mass of compound deposited = $$\frac{\text{Molar mass x Quantity of Electricity}}{\text{96500 x no of charge}}$$

Q = IT

I = 0.5A

T = 45 x 60

T = 2700s

Q = 0.5 x 2700

= 1350c

Molarmass = 64gmol-1

no of charge = + 2

Mass = $$\frac{64 \times 1350}{96500 \times 2}$$

Mass = 0.448g

Question 33
A
3-methybut-3-ene
B
2-methylbut-1-ene
C
2-ethylprop-1-ene
D
2-methylbut-2-ene
##### Explanation
CH2CH2 - CCH3CH2
Start the numbering from the terminal carbon.

Question 34
A
Fe3 + (H2O)6
B
FeO.H2O
C
Fe2O3.3H2O
D
Fe3O4.2H22O
##### Explanation
Iron [Fe] reacts with H2 in the presence of oxygen to form a rust.

4Fe + 3O2 ? 2 Fe2O2

Fe2O3 + H2O ? Fe2O3.H2O

Question 35
A

0.1

B

0.5

C

2

D

4

##### Explanation

The rate of dimension of a gas inversely proportional to the square root of its molecular mass or its density, which is Graham's Law of diffusion of gas.

R $$\frac{1}{\sqrt{Mm}}$$ or R $$\frac{1}{\sqrt{D}}$$

Dx = 0.5gdm-3, Dy = 2gdm-3

R= $$\frac{K}{\sqrt{D}}$$

R$$\sqrt{D}$$ = k

R1$$\sqrt{D_1}$$ = R1$$\sqrt{D_2}$$

Rx$$\sqrt{D_x}$$ = Ry$$\sqrt{D_y}$$

$$\frac{R_x}{R_y}$$ = $$\frac{\sqrt{D_y}}{\sqrt{D_x}}$$

= $$\frac{\sqrt{2}}{\sqrt{0.5}}$$

= 2.0

Question 36
A
sp2 hybridized
B
sp3 hybridized
C
sp4 hybridized
D
sp hybridized
##### Explanation
Alkane's family are sp3 hybridized

Question 37
A

100c

B

273c

C

373c

D

0c

##### Explanation

Where -273c = 0K

i.e -273c + 273 = 0K

At zero kelvin, the volume of a gas becomes zero.

Question 38
A
20
B
32
C
14
D
12
##### Explanation
Molecular mass = vapour density X2

Mm of XO2 = x + 16(2) = x + 32

vapour density = 32

? x + 32 = 32 x 2

x + 32 = 64

x = 64 - 32

x = 32

? the relative molecular mass of X is 32
Relative molecular mass = vapour density x 2

Question 39
A
chlorine
B
sulphur (IV) oxide
C
carbon (IV) oxide
D
ammonia
##### Explanation
Upward delivery works well for hydrogen and ammonia, which are both less densed than air. Sometimes, they are collected over water.

Question 40
A

further heating

B

C

cooling the acid solution with cold water

D

bubbling air through the acid solution

##### Explanation

Bubbling of air through the acid solution removes deposited oxides of nitrogen.

Nitric acid is prepared in the laboratory by heating a nitrate salt with the concentrated acid.
NaNO3 + H2SO4 NaHSO4 + HNO3

Vapours of nitric acid are condensed to a brown liquid in a receiver cooled under cold water. "Dissolved oxides of nitrogen" e.g NO2 are removed by redistillation or blowing a current of carbondioxide or dry air through the warm acid

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