Question

There are two samples of HCL having molarity 1 M and 0.25 M. Find the volumes of these samples taken in order to prepare 0.75M HCl solution.
A)20 ml and 10 ml
B)100 ml and 50 ml
C) 40ml and 20 ml
D) 50ml and 25ml

Answer 1

Since the number of moles of HCl(n) =Molarity*Molar Volume
=>Let V1 be amount in L for solution 1
=>n1=V1*1
Similarly,n2=0.25*V2
no. of moles of solution in the final one is n= 0.75*(V1+V2)
Since no. of moles of a reaction is constant,
=>n1+n2=n
=>V1+0.25V2=0.75(V1+V2)
0.25V1=0.5V2
orV1=2V2
=> The options that are satisfying the criteria are A),B),C),D)
All of the above is the answer.