Which of the following pairs give a positive Tollens test?(A) Glucose, Sucrose(B) Glucose, Fructose(C) Hexanal, acetophenone(D) Fructose, sucrose

The Tollens test is a chemical test used to detect the presence of reducing sugars, which are sugars that can reduce certain metal ions. In a positive Tollens test, a silver mirror is formed in the reaction mixture, indicating the presence of reducing sugars.

Out of the given pairs:

(A) Glucose, Sucrose: Glucose is a reducing sugar, while sucrose is a non-reducing sugar. Therefore, this pair can give a positive Tollens test.

(B) Glucose, Fructose: Both glucose and fructose are reducing sugars, so this pair can also give a positive Tollens test.

(C) Hexanal, Acetophenone: Neither hexanal nor acetophenone is a sugar, so this pair will not give a positive Tollens test.

(D) Fructose, Sucrose: Fructose is a reducing sugar, but sucrose is a non-reducing sugar. Therefore, this pair can also give a positive Tollens test, but the presence of sucrose may interfere with the test.

So, the correct options for a positive Tollens test are (A) Glucose, Sucrose and (B) Glucose, Fructose.