`6.023xx10^(20)` molecules of urea are present in 100 ml of its solution. The concentration of the solution is

Options

A. 0.001 M
B. 0.01 M
C. 0.02 M
D. 0.1 M

Answer

A

Explanation

100 ml of solution contain `6.023 xx 10^(20)` molecules.
`6.023 xx 10^(23)` molecules in 1000 ml = 1 M
`:. 6.023 xx 10^(20)` molecules in 1000 ml=`(1xx6.023xx10^(20))/(6.023xx10^(23))=10^(-3)`
`10^(-3)` moles of present in 100 ml
`:.` In 1000ml the moles present is=`10^(-3)/cancel(100)xxcancel(1000)=10^(-2)` moles
Concentration = 0.01 M