When a solution is added to vanilla extract, then the characteristic smell of vanilla cannot be detected. State whether the given solution is an acid or a base.

4 Name an indicator which is pink in alkaline solution but turns colourless in acidic solution. 5 When a solution is added to a cloth strip treated with onion extract, then the smell of onion cannot be detected. State whether the given solution contains an acid or a base. 7 How will you test for the gas which is liberated when hydrochloric acid reacts, with an active metal? 8 Name the gas evolved when dilute HCL reacts with sodium hydrochloric. How is it recognized?