J.R. S. answered 04/28/19
Ph.D. University Professor with 10+ years Tutoring Experience
If you are being literal, then the volume might actually increase slightly because of the formation of H2O during the neutralization reaction: 2HNO3 + Ca(OH)2 ==> CaCl2 + 2H2O
Looking at the values:
moles HNO3 = 0.01 L x 2 mol/L = 0.02 moles HNO3
moles Ca(OH)2 = 0.01 L x 1 mol/L = 0.01 moles Ca(OH)2
Neither is limiting so 0.02 moles H2O should be formed
0.02 moles H2O x 18 g/mole = 0.36 g H2O
Assuming a density of 1g/ml you'd have an additional 0.36 mls of volume
So, "theoretically", the final volume would be 10 ml + 10 ml + 0.36 ml = 20.36 mls.
HOWEVER, a large amount of heat is also generated in this reaction, and the density of H2O cannot be taken as 1g/ml, so that's another compounding factor.
I'd say that this question can't really be answered completely without significantly more information, but if it was meant to be a exercise in balancing the equation and calculating the water formed, then the above explanation might be suitable.