A potter wishes to make a deep blue glaze. Which one of these available chemicals should be mixed?

A student added blue litmus solution to a colourless aqueous solution. The solution turned red. Which one of the following chemical should be added in excess so that the change in colour is reversed?

Which one is mixed gland?

Which one of the following changes blue litmus red ?

Which one of the following prussian blue colour ?

Which one of the following is mixed ketone?