CBSE Class 10 Answered
Qus: A metal X reacts with HCI to liberate gas A but its compound Y releases gas B with HCI along with the salt CaCl,.
Name the metal X.
• Identify gas A and how will you test for it?
Name the salt Y and give its molecular formula.
• Identify gas B and how will you test for it? What type of reaction takes place when X reacts with HCI?
Salt of X Metal i.e Y reacts with HCl to produce salt CaCl2 and gas B.
(i)As the product CaCl2 is a calcium salt, we can conclude that the reactant Y salt is a Calcium metal salt.
(ii)Carbonates of metal on reacting with HCl produce Chlorides of metal along with release CO2 gas.
From (i) and (ii), the salt must be CaCO3 and the reaction would be as below,
CaCO3 + HCl → CaCl2 + CO2↑
As Y is CaCO3, hence, X must be Calcium metal.
Metals on reaction with HCl produce corresponding chlorides and hydrogen gas. This is Displacement reaction wherein metal displaces hydroen from HCl to form metal chlorides.
Ca + HCl → CaCl2 + H2↑
Thus,
X = Ca
Y = CaCO3
A = H2 gas
The gas A is hydrogen gas which can be confirmed by holding burning candle in the released gas. Hydrogen gas burns with pop sound.
B = CO2 gas
The gas B is carbon dioxide which can be confirmed by lime water test. Carbon dioxide turns lime water milky.