Question

2.5 litre of 1 M NaOH solution are mixed with another 3 litre of 0.5 M NaOH solution Then the molarity of the resulting
A. 0.80 M
B. 1.0 M
C. 0.73 M
D. 0.50 M

Answer 1

Correct Answer - C
Moles of 2.5 L of `1M NaOH = 2.5xx1=2.5`
Moles of 3.0 L of `0.5 M NaOH = 3.0xx0.5=1.5`
Total moles of NaOH in solution
`=2.5+1.5=4.0`
(Total volume of solution `=2.5+3.0=5.5 L`)
Thus, `M_(1)xxV_(1)=M_(2)xxV_(2)`
`4=M_(2)xx5.5`
`therefore` Molarity of resultant solution, `M_(2)=(4)/(5.5)M`
`~~0.73M`