250 mL of a `Na_(2)CO_(3)` solution contains `2.65 g` of `Na_(2)CO_(3). 10mL` of this solution is added to xml of water is obtain `0.001 M Na_(2)CO_(3)` solution. The value of x is :

Options

A. 1000
B. 990
C. 9990
D. 90

Answer

B

Explanation

Molarity of solution
M=`(w_(B)xx1000)/(m_(B)xxV)=(2.65xx1000)/(106xx250)=0.1`
`M_(1)V_(1)=M_(2)V_(2)`
`0.1xx10=0.001(10+x)`
`x=990mL`