Question

Answer the following questions:
1. Define a compound. State three points of evidence to show that sodium chloride is a compound.
2. When Iron powder and Sulphur powder were mixed together and heated strongly, a substance A was formed. When did. Hydrochloric acid was added to substance A, the gas B was evolved.
a) What is A and what type of substance is it?
b) Name the gas B. State one characteristic property of gas B.
c)Is the reaction of Iron and Sulphur powder a chemical change or a physical change.
Answer the question according to the class 9th student.

Answer 1

Answer:

1. A compound is a group of elements that cannot be separated by physical methods.

NaCl is a compound becuse it cannot be separated by physical methods.

It consists of postive and negative ions.

It can be separated only by chemical reactions.

2. (a) A is a mixture of iron and sulphur and it is in liq form.

(b) Gas B is hydrogen gas and it has sharp pungent irritating smell.

(c) It is a physical change.

Explanation: