In the neighborhood of your school, hard water required for an experiment is not available. Select from the following groups of salts available in your school, a group each member of which, if dissolved in distilled water, will make it hard:

A student puts a drop of reaction mixture of a saponification reaction first on a blue litmus paper and then on a red litmus paper. He may observe that:

For preparing soap in the laboratory we require an oil and a base. Which of the following combination of an oil and a base would be best suited for the preparation of soap?

A student while observing an embryo of a pea seed in the laboratory listed various parts of the embryo as given below: On examining the list the teacher remarked that only three parts are correct. Select three correct parts from the following list:

If you are asked to select a group of two vegetables, out of the following, having homologous structures which one would you select?