chemistry (solutions)

Question

0.635g  of a cupric salt was dissolved in water, excess of KI  was added and the liberated iodine required 25ml of N/5Na2S2O3N solution the weight percentage of copper in the salt is ?

Answer 1

The number of Cu²⁺ = 25 × 1/5 = 5 = Number of milli moles

The weight of the copper in cupric salt is:

⇒ 5 × 63.5 × 10^-3 = 0.3175 g

Now, the weight of the copper in 0.635 g of a cupric salt is:

⇒ 0.3175/0.635 = 0.5 g

now, the weight percentage is:

⇒ 0.5 × 100% = 50%