Solutions Question 168
Question: Which of the following should be done in order to prepare $ 0.40M,NaCl $ starting with $ 100,ml $ of $ 0.30M,NaCl $ (mol.wt. of $ NaCl=58.5 $ ) [BIT 1992]
Options:
A) Add $ 0.585,g,NaCl $
B) Add $ 20,ml $ water
C) Add $ 0.010ml,NaCl $
D) Evaporate $ 10ml $ water
Show Answer
Answer:
Correct Answer: A
Solution:
100 ml. of 0.30M $ =\frac{100\times 0.3}{1000}=0.03 $ mole of NaCl 100 ml of 0.40M $ =\frac{100\times 0.4}{1000}=0.04 $ mole of NaCl Moles of NaCl to be added $ =0.04-0.03=0.01,mole $ = 0.585 gm
