What is the difference between "that" and "which"?

That - "That" is used with restrictive phrases. Restrictive phrases are phrase. that are essential to the sentence.

Which - "Which" is used with nonrestrictive phrases. Nonrestrictive phrases are phrases that state non essential information. A phrase is considered nonrestrictive phase if the phase can be omitted from the sentence.

Examples:

• The shirt that you lent me is in my bag.
• The shirt, which is red, is in my bag.
• The house that I wanted to buy has been sold.
• The house, which I didn't want to buy, has been sold.
• The food store that I go to all the time is closed today.
• The store, which is near my house, is not open today.