Question

when 10 ml of H2 and 12.5 M L of cl2 are allowed to react the final mixture contains and at the same conditions

Answer 1

Assuming STP conditions, 10 mL of hydrogen and 12.5 mL of chlorine corresponds to 0.45 and 0.55 millimoles of hydrogen and chlorine respectively.

The reaction is H2+Cl2→2HCl.

Thus, 1 mole of hydrogen reacts with 1 mole of chlorine to form two moles of HCl.

0.45 millimoles of hydrogen will react with 0.45 millimoles of chlorine to form 0.9 millimoles of HCl.

0.1 millimoles of chlorine will remain unreacted.

Thus, the  reaction mixture will contain 0.10 millimoles of chlorine and 0.9 millimoles of HCl.

At STP, this corresponds to 20.16 mL of HCl and 2.24 mL of chlorine.