A solution of NaOH is 4g/l. What volume of HCl gas at STP will neutral

1.	A solution of NaOH is 4g/l. What volume of HCl gas at STP will neutralise, 50 ml of the alkali solution?
Answer» Molar mass of NaOH = 40 g/mole First we have to calculate the mass of NaOH. As, 1L of solution contains 4 g of NaOH So, 0.05 L of solution contains 4 x 0.05 = 0.2 g of NaOH The mass of NaOH = 0.2 g Now we have to calculate the moles of NaOH. The moles of NaOH = Mass of NaOH/ Molar mass of NaOH = (0.2 g)/(40g/mole) = 0.005 mole The moles of NaOH = 0.005 mole Now we have to calculate the moles of HCl. The balanced chemical reaction will be, NaOH + HCl ---> NaCl + H₂O From the balanced reaction we conclude that As, 1 mole of NaOH neutralizes 1 mole of HCl So, 0.005 mole of NaOH neutralizes 0.005 mole of HCl The moles of HCl = 0.005 mole Now we have to calculate the volume of HCl. As we know that at STP, 1 mole of HCl contains 22.4 L volume of HCl So, 0.005 mole of HCl contains 22.4 x 0.005 = 0.112L = 112 ml volume of HCl Therefore, the volume of HCl gas at STP will be, 0.112 L or 112 ml.

A solution of NaOH is 4g/l. What volume of HCl gas at STP will neutralise, 50 ml of the alkali solution?

Answer»

Molar mass of NaOH = 40 g/mole

First we have to calculate the mass of NaOH.

As, 1L of solution contains 4 g of NaOH

So, 0.05 L of solution contains 4 x 0.05 = 0.2 g of NaOH

The mass of NaOH = 0.2 g

Now we have to calculate the moles of NaOH.

The moles of NaOH = Mass of NaOH/ Molar mass of NaOH = (0.2 g)/(40g/mole) = 0.005 mole

The moles of NaOH = 0.005 mole

Now we have to calculate the moles of HCl.

The balanced chemical reaction will be,

NaOH + HCl ---> NaCl + H₂O

From the balanced reaction we conclude that

As, 1 mole of NaOH neutralizes 1 mole of HCl

So, 0.005 mole of NaOH neutralizes 0.005 mole of HCl

The moles of HCl = 0.005 mole

Now we have to calculate the volume of HCl.

As we know that at STP,

1 mole of HCl contains 22.4 L volume of HCl

So, 0.005 mole of HCl contains 22.4 x 0.005 = 0.112L = 112 ml volume of HCl

Therefore, the volume of HCl gas at STP will be, 0.112 L or 112 ml.