Chemical Process Calculation Questions and Answers Part-9

1. The quantity of solute per unit volume is __________
a) Mole
b) Concentration
c) Density
d) None of the mentioned

Answer: b
Explanation: The quantity of solute per unit volume is concentration.

2. Find the correct statement for ppm
a) For solids and liquids, it is mole ratio
b) For gases, it is mole ratio
c) It is mole ration for every phase of matter
d) It is mass ratio for every phase of matter

Answer: b
Explanation: For gases, it is mole ratio and for liquids and solids, it is mass ratio.

3. The concentration of 0.02 M H2SO4 molecules in a solution where the ionization of H2SO4 is 30%.
a) 0.014
b) 0.003
c) 0.002
d) 0.005

Answer: a
Explanation: The remaining concentration of H2SO4 molecules is = 0.02-0.02*0.30.

4. What is the weight fraction of N2 in a gas when it is liquefied? The gas contains 400 ppm of N2 in CO2.
a) 2.54×10-4
b) 3.54×10-4
c) 4.54×10-4
d) 5.54×10-4

Answer: a
Explanation: Basis: 106 mole gas.

5. A student has two solution of a substance. Solution-1: 25M, 400mL and Solution-2: 30M, 300M. What is the molarity of the final solutions if these two solutions are mixed?
a) 27.14
b) 22.14
c) 14.22
d) 14.27

Answer: a
Explanation: M = (M1V1 + M2V2 )/(V1 + V2).

6. What is the total hardness of water in mg/L if the concentration of Ca and Mg are 56.7 mg/L and 9.8 mg/L?
a) 182.1
b) 66.5
c) 133
d) 91.05

Answer: a
Explanation: g CaCO3 /g Ca= 2.5 and g CaCO3 /g Mg = 4.118
Hardness of water = 2.5(56.7) + 4.118(9.8).

7. What is the concentration of 36 grams of water occupying 1 m3 volume?
a) 1 mole / m3
b) 2 mole / m3
c) 11 mole / m3
d) 22 mole / m3

Answer: b
Explanation: Moles of water= 36/18 = 2, Concentration = 2/1= 2 mole / m3.

8. What is the concentration (% m/v) of the solution that contains 20.0 g NaCl in 800.0 mL solution?
a) 5.00%
b) 2.00%
c) 0.200%
d) 2.50%

Answer: d
Explanation: Concentration = 20/800= 0.025 gm/ml.

9. What is the ppm concentration of 6.00 mL sample of solution that has 3.6 x 10-4 g of sodium ions?
a) 20
b) 40
c) 60
d) 80

Answer: c
Explanation: Concentration parts per million.

10. How many mL of 2.50% (m/v) NaOH solution would contain 3.50 g of NaOH?
a) 7
b) 14
c) 21
d) 28

Answer: b
Explanation: % (m/v) = 0.025 = 3.5/v.