‘Which’ is a pronoun which is used to extract information for one or more persons or things. It is also used to add the previously mentioned information.

Sentences:

1. Which mango is the sweetest of them all?

2. Which holiday destination is your favourite?

3. This is the same car which won the race for him.

‘Who’ is a pronoun used to ask about the identity of a particular person. It is also used to give further information about a subject previously mentioned.

Sentences:

1. Who is that guy in a black shirt?

2. Who is this child’s father?

3. This is the same girl who passed out of school 20 years ago.