Q1: The cement becomes unsound by the presence of excess

ANS:D - All of these.

The lime in excess makes the cement unsound and causes the cement to expand and disintegrate.

This ingredient, if present in small amount, imparts hardness and colour to the cement. A high content of magnesia makes the cement unsound.

A very small amount of sulphur is useful in making sound cement. If it is in excess, it causes the cement to become unsound.