10mL of a solution of NaOH is found to be completely neutralised by 8ml of a given solution of HCl. If we take 20 ml of the same solution of NaOH, the amount HCl solution (the same solution as before) required to neutralised it will be -

Q. 10mL of a solution of NaOH is found to be completely neutralised by 8ml of a given solution of HCl. If we take 20 ml of the same solution of NaOH, the amount HCl solution (the same solution as before) required to neutralised it will be -

(a) 4mL (b) 8mL

    (c) 12mL (d) 16mL

Ans. (d) 16mL

How is the decision taken?

Acids and bases neutralise each other in their reaction. When the amount of acid is increased, the amount of base required to neutralise it is also to be increased proportionally. As the amount of NaOH solution is increased to 20 mL from 10mL i.e. two times than before, the amount of HCl solution is also to be increased to 16 mL i.e. two times of 8mL. Hence, the amount of HCl solution (the same solution as before) required to neutralised will be option (d) 16 mL

Q. 15mL of a solution of NaOH is found to be completely neutralised by 9ml of a given solution of HCl. If we take 30 ml of the same solution of NaOH, the amount HCl solution (the same solution as before) required to neutralise it will be - 

        (a) 4mL (b) 18mL

(c) 12mL (d) 16mL

Ans. (b) 18mL

Q. How can the general reaction between a metal oxide and and an acid be written?

Ans. The general reaction between a metal oxide and and an acid can be written as -

        Metal oxide + Acid  Salt + Water

Q. Write balanced equation for the following.

        - Copper chloride and water are produced in the reaction between copper oxide and dilute hydrochloric acid.

Ans.  CuO + 2HCl → CuCl₂ +  H₂O