Solubility of gases and solids; Henry's law — practice questions

Question 1 · difficulty L2 · understanding

If $$\mathrm{O}_{2}$$ gas is bubbled through water at $$303 \mathrm{~K}$$, the number of millimoles of $$\mathrm{O}_{2}$$ gas that dissolve in 1 litre of water is __________. (Nearest Integer) (Given : Henry's Law constant for $$\mathrm{O}_{2}$$ at $$303 \mathrm{~K}$$ is $$46.82 \,\mathrm{k}$$ bar and partial pressure of $$\mathrm{O}_{2}=0.920$$ bar) (Assume solubility of $$\mathrm{O}_{2}$$ in water is too small, nearly negligible)

Question 2 · difficulty L2 · understanding

A company dissolves 'x' amount of CO 2 at 298 K in 1 litre of water to prepare soda water. X = __________ $$\times$$ 10 $$-$$3 g. (nearest integer) (Given : partial pressure of CO 2 at 298 K = 0.835 bar. Henry's law constant for CO 2 at 298 K = 1.67 kbar. Atomic mass of H, C and O is 1, 12, and 6 g mol $$-$$1 , respectively)

Question 3 · difficulty L2 · understanding

CO 2 gas is bubbled through water during a soft drink manufacturing process at 298 K. If CO 2 exerts a partial pressure of 0.835 bar then x m mol of CO 2 would dissolve in 0.9 L of water. The value of x is ____________. (Nearest integer) (Henry's law constant for CO 2 at 298 K is 1.67 $$\times$$ 10 3 bar)

Question 4 · difficulty L2 · understanding

The oxygen dissolved in water exerts a partial pressure of 20 kPa in the vapour above water. The molar solubility of oxygen in water is __________ $$\times$$ 10 $$-$$5 mol dm $$-$$3 . (Round off to the Nearest Integer). [Given : Henry's law constant = K H = 8.0 $$\times$$ 10 4 kPa for O 2 . Density of water with dissolved oxygen = 1.0 kg dm $$-$$3 ]

Question 5 · difficulty L3 · understanding

At 298 K , the mole percentage of $\mathrm{N}_2(\mathrm{~g})$ in air is $80 \%$. Water is in equilibrium with air at a pressure of 10 atm . What is the mole fraction of $\mathrm{N}_2(\mathrm{~g})$ in water at 298 K ? $\left(\mathrm{K}_{\mathrm{H}}\right.$ for $\mathrm{N}_2$ is $\left.6.5 \times 10^7 \mathrm{~mm} \mathrm{Hg}\right)$

• A. $9.35 \times 10^{-5}$
• B. $9.35 \times 10^5$
• C. $1.23 \times 10^{-7}$
• D. $1.17 \times 10^{-4}$

Question 6 · difficulty L3 · understanding

Given below are two statements : Statement I : The Henry's law constant $\mathrm{K}_{\mathrm{H}}$ is constant with respect to variations in solution's concentration over the range for which the solution is ideally dilute. Statement II : $\mathrm{K}_{\mathrm{H}}$ does not differ for the same solute in different solvents. In the light of the above statements, choose the correct answer from the options given below

• A. Both Statement I and Statement II are true
• B. Statement I is true but Statement II is false
• C. Statement I is false but Statement II is true
• D. Both Statement I and Statement II are false

Question 7 · difficulty L3 · understanding

For a solution of the gases A, B, C and D in water at 298 K, the values of Henry's law constant (K H ) are 30.40, 2.34, 1.56 $$\times$$ 10 $$-$$5 and 0.513 k bar respectively. In the given graph, the lines marked as 'p' and 's' correspond respectively to :

• A. A and C
• B. B and A
• C. D and A
• D. C and D

Question 8 · difficulty L3 · understanding

Sea water, which can be considered as a 6 molar $(6 \mathrm{M})$ solution of NaCl , has a density of $2 \mathrm{~g} \mathrm{~mL}^{-1}$. The concentration of dissolved oxygen $\left(\mathrm{O}_2\right)$ in sea water is 5.8 ppm . Then the concentration of dissolved oxygen $\left(\mathrm{O}_2\right)$ in sea water, is $x \times 10^{-4} \mathrm{~m}$. $x=$ ___________. (Nearest integer) Given: Molar mass of NaCl is $58.5 \mathrm{~g} \mathrm{~mol}^{-1}$ Molar mass of $\mathrm{O}_2$ is $32 \mathrm{~g} \mathrm{~mol}^{-1}$

Question 9 · difficulty L3 · understanding

Identify the correct statements : (A) The molality of 2.5 g of ethanoic acid (Molar mass : $60 \mathrm{~g} \mathrm{~mol}^{-1}$ ) in 75 g of benzene solution is 0.556 m . (B) The molarity of a solution containing 5 g of NaOH (molar mass : $40 \mathrm{~g} \mathrm{~mol}^{-1}$ ) in 450 mL of solution is 0.278 M at 298 K . (C) Aquatic species are more comfortable in cold water. (D) The solubility of gas increases with decrease in pressure. (E) For a binary mixture of $A$ and $B$, the number of moles of $A$ and $B$ are $n_A$ and $n_B$ respectively. The mole fraction of $B$ will be $x_B=\frac{n_A}{n_A+n_B}$. Choose the correct answer from the options given below :

• A. A, B and C only
• B. A and B only
• C. A and C only
• D. A, D and E only

Question 10 · difficulty L3 · understanding

The Henry's law constant $$(\mathrm{K}_{\mathrm{H}})$$ values of three gases $$(\mathrm{A}, \mathrm{B}, \mathrm{C})$$ in water are $$145, 2 \times 10^{-5}$$ and $$35 \mathrm{~kbar}$$ respectively. The solubility of these gases in water follow the order:

• A. B > A > C
• B. B > C > A
• C. A > C > B
• D. A > B > C