Question

The chemical reaction between marble and dilute HCl is given. 

CaCO₃ + 2HCl → CaCl₂ + H₂O +CO₂ 

a) Which gas is formed here? How can you identify this gas? 

b) Suggest any two ways you would choose to increase the rate of this chemical reaction. Explain the reason.

Answer 1

(a) Carbon dioxide (CO₂). Show a burning splinter in the gas. It will get extinguished. 

or 

Show a glass rod dipped in clear lime water into the gas. The lime water will turn milky 

(b) 

(1) Use powdered marble 

(2) Use concentrated HCl 

(3) Heat the mixture.