Question

Can u say a double displacement reaction where gas is evolved?

Answer 1

A double displacement reaction, also known as a double replacement reaction or metathesis, is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.

for eg-

A double displacement occurs, giving us carbonic acid and calcium chloride. But, carbonic acid always breaks down into water and carbon dioxide, our gas product.

Answer 2

CaCO3 + 2HCl gives CaCl2 + CO2 +H2O

here CO2 is the required gas cl displaces CaCO3 from calcium and then forms CaCl2 and the remaing CaCO3 and 2H are released as co2 and h20