Answer:
(d) In the presence of sulfuric acid, calcium chloride reacts to form hydrogen chloride.
Explanation:
It's because it lowers the melting point of the ice / etc so I think it is, but check it yourself too!
Answer: 16.32 g of 
as excess reagent are left.
Explanation:
To calculate the moles :
According to stoichiometry :
2 moles of 
require = 1 mole of
Thus 0.34 moles of will require=
of
Thus is the limiting reagent as it limits the formation of product and is the excess reagent.
Moles of left = (0.68-0.17) mol = 0.51 mol
Mass of 
Thus 16.32 g of as excess reagent are left.
