18 + Interview Questions in GENERAL QA IN SOLUTIONS Page 1 InterviewSolution

1.	Why NaCl is used to clear snow from roads ?
Answer» It lowers freezing point of water.

Discussion

2.	The gas phase decomposition of acetaldehyde CH3 CHO => CH4 + CO follows the rate law, Rate = k(PCH3CHO)3/2, unit of P is atm and time is second. What are the units of its rate constant ?
Answer» your the answer Atm-^½ sec-¹

2.

The gas phase decomposition of acetaldehyde CH3 CHO => CH4 + CO follows the rate law, Rate = k(PCH3CHO)3/2, unit of P is atm and time is second. What are the units of its rate constant ?

Answer»

your the answer

Atm-^½ sec-¹

Discussion

3.	Based on solute-solvent interactions, arrange the following in order of increasing solubility in n-octane and explain. Cyclohexane, KCl, CH3OH, CH3CN.
Answer» n-octane is a non-polar solvent. Therefore, the solubility of a non-polar solute is more than that of a polar solute in the n-octane. The order of increasing polarity is: Cyclohexane < CH₃CN < CH₃OH < KCl Therefore, the order of increasing solubility is: KCl < CH₃OH < CH₃CN < Cyclohexane

3.

Based on solute-solvent interactions, arrange the following in order of increasing solubility in n-octane and explain. Cyclohexane, KCl, CH3OH, CH3CN.

Answer»

n-octane is a non-polar solvent. Therefore, the solubility of a non-polar solute is more than that of a polar solute in the n-octane.

The order of increasing polarity is:

Cyclohexane < CH₃CN < CH₃OH < KCl Therefore, the order of increasing solubility is: KCl < CH₃OH < CH₃CN < Cyclohexane

Discussion

4.	Suggest the most important type of intermolecular attractive interaction in the following pairs. (i) n-hexane and n-octane (ii) I2 and CCl4 (iii) NaClO4 and water (iv) methanol and acetone (v) acetonitrile (CH3CN) and acetone (C3H6O).
Answer» (i) Van der Wall’s forces of attraction. (ii) Van der Wall’s forces of attraction . (iii) Ion-diople interaction. (iv) Dipole-dipole interaction. (v) Dipole-dipole interaction.

4.

Suggest the most important type of intermolecular attractive interaction in the following pairs. (i) n-hexane and n-octane (ii) I2 and CCl4 (iii) NaClO4 and water (iv) methanol and acetone (v) acetonitrile (CH3CN) and acetone (C3H6O).

Answer»

(i) Van der Wall’s forces of attraction.

(ii) Van der Wall’s forces of attraction

. (iii) Ion-diople interaction.

(iv) Dipole-dipole interaction.

(v) Dipole-dipole interaction.

Discussion

5.	Why is liquid ammonia bottle first cooled in ice before opening it?
Answer» At room temperature, the vapour pressure of liquid ammonia is very high. On cooling vapour pressure decreases, therefore the liquid ammonia will not splash out

Discussion

6.	Calculate the molarity of pure water (d = 1 g mL-1).
Answer» Desity of water = 1 g mL^-1 Mass of 1000 ml of water = V xd = 1000 mL x 1 gm^-1 = 1000 g Moles of water 1000/18= 55.55 mol Now, mole of H₂O present in 1000 mL or 1 L of water. So, molarity = 55.55M

6.

Calculate the molarity of pure water (d = 1 g mL-1).

Answer»

Desity of water = 1 g mL^-1

Mass of 1000 ml of water = V xd

= 1000 mL x 1 gm^-1

= 1000 g

Moles of water 1000/18= 55.55 mol

Now, mole of H₂O present in 1000 mL or 1 L of water.

So, molarity = 55.55M

Discussion

7.	The dissolution of ammonium chloride in water is endothermic process. What is the effect of temperature on its solubility ?
Answer» Since dissolution of NH₄Cl in water is endothermic process, its solubility increases with rise in temperature (i.e., Le-Chatelier process).

Discussion

8.	What is van't Hoff factor? How is it related with :(a) degree of dissociation (b) degree of association
Answer» (a) α = i - 1/n -1 (b) α = i - 1/1/n - 1

8.

What is van't Hoff factor? How is it related with :(a) degree of dissociation (b) degree of association

Answer»

(a) α = i - 1/n -1

(b) α = i - 1/1/n - 1

Discussion

9.	What do analogus organs explain as an evedence of organic evolution.
Answer» Analogous organs give evidence. evolution coming from two directions. which means that they serve the same function in different species but they evolved independently rather than from the same embryological material or from the same structures in a common ancestor.

Discussion

10.	What is Vanít Hoff factor ?
Answer» It is the ratio of normal molecular mass to observed molecular mass. It is denoted as i. i = normal molecular mass/observed molecular mass = no. of particles after association or dissociation/no. of particles before

10.

What is Vanít Hoff factor ?

Answer»

It is the ratio of normal molecular mass to observed molecular mass. It is denoted as i.

i = normal molecular mass/observed molecular mass

= no. of particles after association or dissociation/no. of particles before

Discussion

11.	Why the boiling point of solution is higher than pure liquid ?
Answer» Due to lowering in vapour pressure

Discussion

12.	Henry law constant for two gases are 21.5 and 49.5 atm, which gas is more soluble ?
Answer» K_H is inversely proportional to solubility As S = kh × X i.e. solubility = Henry constant × mole fraction So, S is directly proportional to Kh. Hence, higher the value of kh, higher will be its S. Hence 49.5 is the answer .

Discussion

13.	a ) camphorB) naphthalene C) benzeneD) water
Answer» Freezing occurs when liquid solvent is in equilibrium with solid solvent. As non volatile solute decreases, the vapour pressure freezing point decreases. Camphor has the maximum value of K_f(=39.7).

13.

a ) camphorB) naphthalene C) benzeneD) water

Answer»

Freezing occurs when liquid solvent is in equilibrium with solid solvent. As non volatile solute decreases, the vapour pressure freezing point decreases.

Camphor has the maximum value of K_f(=39.7).

Discussion

14.	Why the molecular mass becomes abnormal ?
Answer» Due to association or dissociation of solute in given solvent

Discussion

15.	Define molarity. How it is related with normality ?
Answer» N = M x Basicity or acidity number of moles of solute per 1 litre of solution normality/n factor = molarity

15.

Define molarity. How it is related with normality ?

Answer»

N = M x Basicity or acidity

number of moles of solute per 1 litre of solution

normality/n factor = molarity

Discussion

16.	How molarity is related with percentage and density of solution ?
Answer» Answer: M = P xd x 10/M.M₂.

Discussion

17.	What role does the molecular interaction play in the solution of alcohol and water ?
Answer» Positive deviation from ideal behaviour

Discussion

18.	A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution
Answer» Total amount of solute present in the mixture is given by 300x25/100+400x40/100 , = 75 + 160 = 235 g Total amount of solution = 300 + 400 = 700 g 235/700x100% Therefore, mass percentage (w/w) of the solute in the resulting solution, = 33.57% And, mass percentage (w/w) of the solvent in the resulting solution, = (100 − 33.57)% = 66.43%

18.

A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution

Answer»

Total amount of solute present in the mixture is given by

300x25/100+400x40/100

, = 75 + 160

= 235 g

Total amount of solution = 300 + 400 = 700 g

235/700x100%

Therefore, mass percentage (w/w) of the solute in the resulting solution,

= 33.57%

And, mass percentage (w/w) of the solvent in the resulting solution,

= (100 − 33.57)%

= 66.43%

Discussion

Explore topic-wise InterviewSolutions in .

Why NaCl is used to clear snow from roads ?

The gas phase decomposition of acetaldehyde CH3 CHO =&gt; CH4 + CO follows the rate law, Rate = k(PCH3CHO)3/2, unit of P is atm and time is second. What are the units of its rate constant ?

Based on solute-solvent interactions, arrange the following in order of increasing solubility in n-octane and explain. Cyclohexane, KCl, CH3OH, CH3CN.

Suggest the most important type of intermolecular attractive interaction in the following pairs. (i) n-hexane and n-octane (ii) I2 and CCl4 (iii) NaClO4 and water (iv) methanol and acetone (v) acetonitrile (CH3CN) and acetone (C3H6O).

Why is liquid ammonia bottle first cooled in ice before opening it?

Calculate the molarity of pure water (d = 1 g mL-1).

The dissolution of ammonium chloride in water is endothermic process. What is the effect of temperature on its solubility ?

What is van't Hoff factor? How is it related with :(a) degree of dissociation (b) degree of association

What do analogus organs explain as an evedence of organic evolution.

What is Vanít Hoff factor ?

Why the boiling point of solution is higher than pure liquid ?

Henry law constant for two gases are 21.5 and 49.5 atm, which gas is more soluble ?

a ) camphorB) naphthalene C) benzeneD) water

Why the molecular mass becomes abnormal ?

Define molarity. How it is related with normality ?

How molarity is related with percentage and density of solution ?

What role does the molecular interaction play in the solution of alcohol and water ?

A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution

The gas phase decomposition of acetaldehyde CH3 CHO => CH4 + CO follows the rate law, Rate = k(PCH3CHO)3/2, unit of P is atm and time is second. What are the units of its rate constant ?