distinguish between-

1) isopropyl alcohol n-propyl alcohol

2) pentane-2-one pentane-3-one

3) propan-1-one propan-2-one

1) Difference between isopropyl alcohol and n-propyl alcohol:

n-propyl and isopropyl can be distinguished by lucas test. Lucas Test is a test which is used to distinguish between primary, secondary and tertiary alcohols. This test is carried out with the help of Lucas reagent, which is a solution of anhydrous Zinc Chloride and concentrated hydrochloric acid (ZnCl2 + HCl). It is based on the difference between the reactivity of primary, secondary and tertiary alcohols with hydrogen halides. The general equation for the reaction is
ROH + HCl + ZnCl_​2 → RCl + H₂O

When the reagent is added to tertiary alcohol, a turbidity or cloudiness appears in solution instantaneously. This occurs because the alkyl halide so formed is not water soluble. When the reagent is added to secondary alcohol, turbidity appears after 4-5 minutes. However, with primary alcohols, no turbidity appears, suggesting that no reaction occurs with primary alcohol at room temperature.

2) Difference between pentan-2-one and pentan-3-one:

Pentan-2-one and pentan-3-one can be distinguished by iodoform test.
Iodoform test:
Pentan-2-one is a methyl ketone. Thus, it responds to this test. But pentan-3-one not being a methyl ketone does not respond to this test.

3) Propan-1-one is not possible. It should be propanal and propan-2-one:
Propanal and propan-2-one can be distinguished by iodoform test. 
Iodoform test: 
Propan-2-one is  a methyl ketone. Thus, it responds to this test. But propanal does not respond to this test.