Substrate affinity to enzyme in Competitive inhibition
Significance of Km (Michaelis Constant):

Km is substrate concentration at 1/2 Vmax
Constant for an enzyme substrate pair
It is called signature of the enzyme
Higher the Km, lower is the affinity of the enzyme towards the substrate
Lower the Km, higher is the affinity of the enzyme towards the substrate.

Features of competitive inhibition:

Km increases, hence the affinity is lowered
Vmax remains the same.

Features of noncompetitive inhibition:

Km remains the same
Vmax decreases.
Decreases
Increases
Any of the above
Does not change