When a student put some copper turnings in a colourless solution, he observed that the solution gradually turned blue. The solution is most likely to be:

The solution in a beaker turns blue if

The solution in a beaker turns blue if

A student was given an unknown solution in a test tube. When he added universal indicator solution to the test tube the solution turned violet. The unknown solution is most likely to be:

The solution turns blue litmus red, its pH is likely to be………………….,

When a student added a few drops a methyl orange indicator to a colourless solution, the solution turned red. Which of the following should he added in excess so that the colour changes to yellow?