Question

3. 4 g of solid NaOH was dissolved in water and the
solution was made up to 1000 ml. The whole of
this will neutralized completely
(1) 100 ml of 1 M H, SO4
(2) 20 ml of 2.5 M H2SO4
(3) 20 ml of 1.5 M H2SO4
(4) 30 ml of 5 M H2SO4​

Answer 1

Answer:

(2) 20 ml of 2.5 M H2SO4 is the correct answer.

Explanation:

Given data:

Weight of solid NaOH = 4 grams.

It was dissolved in water.

Final volume of solution = 1000 ml.

To find:

Miles after complete neutralization:

Solution:

Molecular mass of sodium hydroxide = 40

We know that

To find molarity

Molarity = no of Moles of solute/volume in 1000 ml

= 0.1*1000/1000

= 0.1

Now we need to calculate the normality

It is given by

Normality = Molarity * n

Here n= 1

Thus

Normality = 0.1*1

=0.1 N

Now we have to determine molarity in complete neutralization

Acid = base

1*0.1 = 0.1

Now if we look at the options

n = 2 for H2SO4

Hence, the number of moles =

0.1/2

=0.05

Now when we see option (2) 20 ml of 2.5 M H2SO4

We found that

Moles = 2.5*20/1000

= 0.05

Hence,

(2) 20 ml of 2.5 M H2SO4 is the correct answer.