What will be the colour of methyl orange in dilute sulphuric acid? 

While eating a midday meal, some sabzi fell on Kusum's clothes. She went home and rubbed some soap on the spot which turned red. Can you give the reason for the change in colour? 

Suresh is a visually disabled student. Which indicators can he use to identify acids and bases? Give two examples. 

Explain the reaction between metals and dilute hydrochloric acids with the help of an example. 

Write the balanced chemical equation of the reaction between calcium hydrogen carbonate and hydrochloric acid.