What are alkalis and alkalines? What is the difference between these Explain.

Vankarbhaibhas explained the definition of an acid and a base, given by Robert Boyle in the classroom. Then the students of the classroom gave some suggestions regarding acid and base. Which suggestion is wrong among these?

Prashant: Acids are sour in taste and bases are bitter.

Dhruvi: Acid does not give any effect on wet blue litmus paper while base turns blue litmus paper blue.

Seil: Acid liberates dry hydrogen gas $\left({\mathrm{H}}_2\right)$ by the reaction with the metal. The base does not react with all metals.

Jaydeep: By neutralisation reaction between acid and base, salt and water is produced.

What is an alkali? Do basic solutions also have ${\mathrm{H}}^{+}$(aq) ions? If yes, then why are these basic? 

The salt solution which does not react with ammonium hydroxide is:

Which acid is present in each of the following? 

(a) Sour milk (b) Tamarind (c) Orange.

An indicator is added to Potassium Hydroxide and the solution turns pink:

Name the indicator that is added.

Pratyush took sulphur powder on a spatula and heated it. He collected the evolved by inverting a test tube over it. What will be the action of gas on the following?

Dry litmus paper.

An indicator is added to Potassium Hydroxide and the solution turns pink:

What is the colour change you will observe if you add litmus to the same solution?

Pratyush took sulphur powder on a spatula and heated it. He collected the evolved by inverting a test tube over it. What will be the action of gas on the following?

Moist litmus paper.