You are given two sample of HCl with molarity 0.341 and 0.143 , volume of each sample being 1 litre. What will be the maximum volume of 0.243 M HCl that can be obtained mixing the given samples in the following two conditions ?
(i) When water is added for dilution
(ii) When no water is added.

Answer

(i) 2.0204 litres ; (ii) 1.98 litre]

Explanation

(i) Let x litre of 0.341 M HCl and 1 litre of 0.143 M HCl be mixed to obtain 0.243 M HCl
`M_(1)V_(1)+M_(2)V_(2)=M_(R)(V_(1)+V_(2))`
`0.341xxx+0.143xx1=0.243(1+x)`
`(0.341-0.243)x=0.243-0.143`
`0.098x=0.1`
`x=1.0204` litre
Total volume `= 1+x = 2.02204` litre
Since, volume is greater than 2 litre, hence water is to be added (ii) Let x litre of 0.143 M HCl and 1 litre of 0.341 M HCl are mixed to obtain 0.243 M HCl
`M_(1)V_(1)+M_(2)V_(2)=M_(R)(V_(1)+V_(2))`
`0.143xxx+0.341xx1=0.243(1+x)`
`0.1x=0.098`
`x=0.98` litre
Total volume `= 1+x = 1.98` litre
Since, volume is less than two litres, no water is to be added.]