Question

250 ml of a sodium carbonate solution contains 2.65 grams of `Na_(2)CO_(3)`. If 10 ml of this solution is diluted to one litre, what is the concentration of the resultant solution (mol. Wt. of Na_(a)`CO_(3)=106`)
A. (a)0.1 M
B. (b)0.001 M
C. (c )0.01 M
D. (d)`10^(-4)M`

Answer 1

Correct Answer - B
Molarity`=(W(g)xx1000)/("molecular wt". xxV(ml.))`
`=(2.65xx1000)/(106xx250)=0.1 M`
`10 ml` of this solution is diluted to `1000 ml N_(1)V_(1)=N_(2)V_(2)`
`10xx0.1-1000xxx`
`x=(0.1xx10)/1000=0.001 M`