Question

10 mL of 0.2 N HCl and 30 mL of 0.1 N HCl together exactly neutralises 40 mL of solution of NaOH which is also exactly neutralised by a solution in water of 0.61 g of an organic acid. What is the equivalent weight of the organic acid?

• A. 61
• B. 91.5
• C. 122
• D. 183

Answer 1

The correct option is C 122

$1geqHCl\equiv 1geqNaOH\equiv geqacid$
The number of g eq of HCl $=\frac{10mL}{1000mL/L}\times 0.2N+\frac{30mL}{1000mL/L}\times 0.1N=0.005eq$
This corresponds to 0.005 g eq of acid.
The equivalent weight of the acid is $\frac{0.61g}{0.005geq}=122$.