Question

In a titration, 25 $cm^3$ of 0.1 N oxalic acid solution requires 20 $cm^3$ of sodium hydroxide for complete neutralization. The mass of sodium hydroxide in 250 $cm^3$ solution is

• A. 12.5 g
• B. 1.25 g
• C. 0.125 g
• D. 125 g

Answer 1

Answer: (B)

1.25 g

Answer 2

Oxalic acid ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? NaOH
$V_1 = 25\, cm^3, N_1 = 0.1\, N$ ? ? $V_2 = 20\, cm^3, N_2 =?$
$N_1V_1 = N_2V_2$
$0.1 \times 25 = N_2 \times 20$
$N_2 = 0.125\, N$
$N = \frac{w \times 100}{Ewt \times V} \Rightarrow 0.125 = \frac{w \times 1000}{40 \times 250}$
$\Rightarrow \:\: w = 1.25 \, g$