What are the precautions taken when we use ACID AND ALKALIES?

What are the features of ACID AND ALKALIES?

You are working as a volunteer in an AIDS awareness programme. If a person comes to you and asks the following questions, how will you answer? What are the precautions to be taken to prevent AIDS?

-------------------------- is used in chemical experiments to ascertain the presence of ACID AND ALKALIES.

The substances that help to identify ACID AND ALKALIES are

A group of students are given a project for constructing a telescope and they were supplied with two biconvex lens of power 1 dioptre and 0.1 dioptre. Prepare a notice label about the precaution to be taken while using the telescope and limitations of the telescope constructed.