Answer: The concentration, in moles per litre, of a solution formed when 13.0 g of calcium hydroxide is dissolved in 5.0 L is 0.036 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

where,
n = moles of solute
= volume of solution in L
moles of
= 
Now put all the given values in the formula of molality, we get

Therefore, the concentration, in moles per litre, of a solution formed when 13.0 g of calcium hydroxide is dissolved in 5.0 L is 0.036 M
The answer is the second one 2.3 X 10-3 dm3
18.is D
19.is A
hope it's correct