8g of NaOH is dissolved in 18g of H2O. Mole fraction of NaOH in solution and molality (in mol kg-1) of the solutions respectively are :

Question

8g of NaOH is dissolved in 18g of H2O. Mole fraction of NaOH in solution and molality (in mol kg-1) of the solutions respectively are : (A) 0.167, 11.11 (B) 0.2, 22.20 (C) 0.2, 11.11 (D) 0.167,22.20

Tardigrade Admin · Accepted Answer

8g NaOH, mol of NaOH = (8/40) = 0.2 mol 18g H2O, mol of H2O = (18/18) = 1 mol ∴ XNaOH = (0.2/1.2) = 0.167 Molality = (0.2 × 1000/18) =11.11 m

Q. $8 g$ of $N a O H$ is dissolved in $18 g$ of $H_{2} O$ . Mole fraction of $N a O H$ in solution and molality (in mol $k g^{- 1})$ of the solutions respectively are :

0.167, 11.11

0.2, 22.20

0.2, 11.11

0.167,22.20

$8 g N a O H$ , mol of $N a O H$ = $\frac{8}{40} = 0.2 m o l$
$18 g H_{2} O$ , mol of $H_{2} O$ = $\frac{18}{18} = 1 m o l$
$∴ X_{N a O H} = \frac{0.2}{1.2} = 0.167$
$M o l a l i t y = \frac{0.2 \times 1000}{18} = 11.11 m$

Q. 8g of NaOH is dissolved in 18g of H2​O. Mole fraction of NaOH in solution and molality (in mol kg−1) of the solutions respectively are :