Question

A solution of naoh is 4g/l what volume of hcl gas at stp will neutralize 50 ml of alkali solution

Answer 1

The correct answer is Option 2. 112 ml.

Explanation:

Given:

NaOH in 1l of solution= 4g/l

Therefore,

Molar mass of NaOH = 40 g/mole

Step 1:

To calculate the mass of NaOH.

From given statement we have,

1l of solution contains 4 g of NaOH.

Therefore,

0.05l of solution will have,

4x0.05=0.2g

Hence mass of NaOH is 0.2g

Step 2:

To find the number moles of NaOH.

We know that,

Number of moles=mass/molar mass

We have mass=0.2g, molar mass of NaOH=40g/mole

Let us substitute the values in the expression we get,

Number of moles=0.2/40

=0.005 moles

Hence the number of moles of NaOH is determined to be as 0.005 moles.

Step 3:

To find the moles of HCl.

We have chemical equation as,

NaOH+HCl=NaCl+ H2O …………..eqn 1

From the above eqn 1,

1 mole of NaOH = 1 mole of HCl

Similarly,

0.005 mole of NaOH = 0.005 mole of HCl

Therefore HCl has 0.005 moles

Step 4:

To find the volume of HCl.

We know that,

1 mole of HCl contains 22.4 L volume of HCl [from STP]

0.005 mole of HCl contains

22.4 x 0.005=0.112l

Hence volume of HCl is found to be as 0.112 l in 0.005 moles of HCl.