Question

A 0.885 M solution of KBr whose initial volume is 76.5 mL has more water added until its concentration is 0.500 M. What is the new volume of the solution?

Answer 1

Answer:

135mL (approx)

Explanation:

We know, Molarity M = n/V

Where n is number of moles of solute in solution and V is volume in litres of solution.

So n = MV

In this M and V changes but n will be constant.

So Mi×Vi = Mf×Vf= n

Where subscript i denotes initial value and subscript f denotes final value.

Given Mi= 0.885M , Vi= 76.5mL = 76.5/1000 = 0.0765L ( as volume should be in litres )

Mf= 0.500M

So putting these,

0.885M×0.0765L = 0.500M×Vf

Vf= 0.885×0.0765L/0.500= 0.135L = 135mL

So new volume would be 135mL