The answer is d. calcium silicide is added to liquid steel to increase the steel's ability to freeze
I would probally say,
Can ants survive a plane ride?
Answer: 448 g of 
will be required to completely react with 784g moles of CO(g) during this reaction.
Explanation:
To calculate the moles :
The balanced chemical equation is:
According to stoichiometry :
2 moles of 
require = 1 mole of
Thus 28 moles of will require=
of
Mass of 
Thus 448g of will be required to completely react with 784g moles of CO(g) during this reaction.
The mass of sodium chloride : 3.5 g
<h3>Further explanation</h3>
Given
Reaction :
2.5g of sodium sulphate + 4.5g of barium chloride ⇒ 3.5g of barium sulphate + sodium chloride
Required
The mass of sodium chloride
Solution
Conservation of mass applies to a closed system, <em>where the masses before and after the reaction are the same</em>
From the reaction :
mass of reactants = 2.5 g + 4.5 g = 7.0 g
mass of products = 3.5 g + mass of sodium chloride
mass of reactants = mass of products
7.0 g = 3.5 g + mass of sodium chloride
mass of sodium chloride = 7 g - 3.5 g =3.5 g
