Some Basic Concepts Of Chemistry Question 307
Question: 250 ml of a sodium carbonate solution contains 2.65 grams of $ Na _2CO _3 $ . If 10 ml of this solution is diluted to one litre, what is the concentration of the resultant solution (mol. wt. of $ Na _2CO _3 $ =106) [EAMCET 2001]
Options:
A) 0.1 M
B) 0.001 M
C) 0.01 M
D) $ {10^{-4}}, $ M
Show Answer
Answer:
Correct Answer: B
Solution:
Molarity $ =\frac{W(gm)\times 1000}{\text{molecular wt}\text{.}\times \text{V(}ml.\text{)}} $
$ =\frac{2.65\times 1000}{106\times 250}=0.1M $
10ml of this solution is diluted to 1000ml $ N _1V _1=N _2V _2 $
$ 10\times 0.1=1000\times x $
$ x=\frac{0.1\times 10}{1000}=0.001M $ .
