Question

4.0 g of caustic soda (mol mass 40) contains same
number of sodium ions are present in
give me solution
​

Answer 1

Hey Dear,

We have to solve this problem by trial & error method.

◆ Answer -

(C) 100 ml of 0.5 M Na2SO4

◆ Explanation -

No of sodium ions present in caustic soda soln -

N = Weight / Molar mass × Avogadro's number

N = 4 / 40 × NA

N = 0.1 NA

For Na2SO4 solution, molarity is calculated by -

Molarity = moles of solute / volume of soln

0.5 = n' / 0.1

n' = 0.05 mol

No of sodium ions released in Na2SO4 soln is given by -

N' = basicity × moles of solute × Avogadro's number

N' = 2 × 0.05 × NA

N' = 0.1 × NA

N' = 0.1 NA

Hence, N = NA

* You can also calculate no of Na+ ions in other options to verify this.

Answer 2

Answer:

Ans. (C) 100 ml of 0.5M Na2S04