Some Basic Concepts Of Chemistry Question 253
Question: 100 ml of 0.1 N hypo decolourised iodine by the addition of x g of crystalline copper sulphate to excess of KI. The value of ?x? is (molecular wt. of $ CuSO _4.5H _2O $ is 250)
Options:
A) 5.0 g
B) 1.25 g
C) 2.5 g
D) 4 g
Show Answer
Answer:
Correct Answer: C
Solution:
$ \overset{+2}{\mathop{CuSO _4}},+2KI\to K _2SO _4+\overset{+2,}{\mathop{CuI _2}}, $ ; $ 2\overset{+2,}{\mathop{CuI _2}},\to \overset{+1,}{\mathop{CuI _2}},+I _2 $
$ I _2+2Na _2S _2O _3\to 2NaI+Na _2S _4O _6 $
Eq. wt. Of $ CuSO _4.5H _2O=Mol\text{. wt}\text{.}=250 $
100 ml of 0.1 N hypo º 100 ml of 0.1 N $ CuSO _4.5H _2O $
$ =\frac{250\times 0.1\times 100}{100}=2.5,gm $
