Based on the law of conservation of angular momentum, what would happen to a collapsing cloud of gas and dust--isolated in space with no external forces--as its size decreases?

The cloud will spin faster.

Explanation:

According to law of conservation of angular momentum, when the mass size is same, if the size of the collapsing cloud decrease, its it angular velocity should increase.

Angular momentum L = mrω^2

Since L and m is constant, to keep L same. when r is decreased ω must increase. Therefore, the cloud will spin faster.