Question

How many kilograms of wet NaOH containing 12% water are required to prepare 60 litres of 0.50 N solution ?

(A) 1.36 kg 

(B) 1.50 kg 

(C) 2.40 gm 

(D) 3.16 kg

Answer 1

Correct Option (A) 1.36 kg 

Explanation: 

One litre of 0.50 N NaOH contains = 0.50 x 40g = 20 g = 0.020 kg

:.   60 litres of 0.50 N NaOH contain

= 0.020 × 60 kg = 1.20 kg NaOH

Since the given NaOH contains 12% water, the amount of pure NaOH in 100 kg of the given

NaOH = 100 – 12 = 88 kg

Thus 88 kg of pure NaOH is present in 100 kg wet NaOH

:. 1.20 kg of pure NaOH is present in 100/88 x 1.20 = 1.36 kg wet NaOH