Two glass jars A and B are filled with carbon dioxide and oxygen gases respectively. In each jar, a lighted candle is placed simultaneously. In which jar, will the candle remain lighted for a longer time and why?

In jar B, the candle remains light for a longer time because oxygen is a supporter of combustion. So, we can say that oxygen (air) is necessary for combustion to take place.

 In Jar A candle will not burn due to lack of oxygen.