(P) Tollens' test

Aldehyde give positive tollen's test but ketones do not give this test.

(Q) 2,4-DNP test

2,4-DNP test is used for the identification of Carbonyl compounds.
Carbonyl compounds give positive 2,4-DNP test.

(R) Iodoform test

Iodoform test is used to check the presence of carbonyl compounds with the structure or alcohols with the structure in a given unknown substance.
In iodoform test methyl-keto group present compound reacts with and base and gives yellow precipitation of .
(S) Fehling solution

In Fehling solution test aldehyde gives red ppt. of and ketones do not show any reaction also alcohols does not give Fehling solution test.
(T) Lucas reagent

It is used to differentiate and categorize primary, secondary, and tertiary alcohols using a solution of anhydrous zinc chloride in concentrated hydrochloric acid.
This solution is commonly referred to as the Lucas reagent. Primary Alcohol gives white turbidity after heating. Secondary Alcohol gives white turbidity after 3-5 min. Tertiary Alcohol gives white turbidity immediately. Pair of compounds can be differentiated by Iodoform test.

So,

Pair of compounds can be differentiated by tollens' test and Iodoform test.

So, ( )

Pair of compounds can be differentiated by tollens' test and fehling's test.

So, ( )

Pair of compounds can be differentiated by tollens' test and fehling's test.

So, ( )