Question

21. Rahul dropped 150 g of marble chips into 1 kg of HCI
solution containing 0.1 of its weight of pure acid. The
mass of marble chips that remained undissolved will
approximately be :
[IJSO-Stage-1V2013]
(A) 6.50 g
(B) 13 g
(C) 26 g.
(D) 15 g.​

Answer 1

Explanation:

Moles of CaCO3=100200=2 moles

Moles of HCl=36.5100=2.74 moles

CaCO3+2HCl⟶CaCl2+CO2+H2O 

    2              2.74 

 0.63                                  1.37        1.37        1.37

→HCl is limiting.

→0.63 moles of CaCO3 i.e., 63 gms remains undissolved.

→1.37 moles of CaCl2 are formed, Mass =111×1.37=152.67 gm

→1.37 moles of CO2 are formed, Mass =44×1.37=60.28 gm