Analytical Chemistry Question 269

Question: To a 25 ml of $ H_2O_2 $ solution, excess of acidified solution of KI was mixed. The liberated I2 require 20ml of 0.3M hypo solution for neutralization. The volume strength of $ H_2O_2 $ will be

[MP PET 2003]

Options:

A) 1.34 ml

B) 1.44 ml

C) 1.60 ml

D) 2.42 ml

Show Answer

Answer:

Correct Answer: A

Solution:

20 ml of $ 0.3N $

$ Na_2S_2O_3 $

$ =20ml $ of $ 0.3NI_2 $ Solution $ =20ml $ of $ 0.3NH_2O_2 $ solution $ \equiv 25ml $ of $ 0.08NH_2O_2 $ solution Mass of $ H_2O_2 $

$ 100ml $ solution = $ \frac{0.08\times 17\times 100}{1000} $

$ =0.136gm $ % = 0.136 $ 68gmH_2O_2 $ evolve oxygen at NTP $ =22400ml $

$ 0.00136gmH_2O_2 $ evolve oxygen at NTP $ =\frac{22400}{68}\times 0.00136=0.448 $ For $ 0.1N $ , the solution is of 0.448 volume.
$ \therefore $ $ 3N $ , volume $ =0.448\times 3=1.344ml $ .