1. Ichha was watching an advertisement on T.V. showing testing a soap with litmus paper.

Can you think, what was actually being depicted through this advertisement. What should

be the nature of soap that we generally use?

2. Manjul would often observe her mother working in the kitchen. She would even see that her

mother preferred cutting the fruits & vegetables very close to the time of consumption. She

even observed that if fruits & vegetables were cut & kept in open, their colour would

change. Can you answer why?

3. Rohini’s science teacher asked the students of her class to bring some soil and some gram

seeds from their house. The next day, she asked them to put the soil in plastic cups & put

the seeds in them, so that they could germinate. The students were asked to water the

seeds everyday. Gradually, it was observed that some of the seeds germinate soon, while

others were delayed. At the same time, there were some cups that required lot of water

while other retained water for a longer period of time.

4. Roopam would often hear about the brand power. She was not exactly sure to what is

brand means. She just knew that all electronic appliances that we buy should have an ISI

mark on it. Can you explain, what an ISI mark is & why should we buy things with ISI mark

on them?

5. Three bottles contain different colourless solutions. The bottles are labeled X, Y and Z.

One bottle contains dilute hydrochloric acid, one contains sodium hydroxide and one

contains water. You have blue and red litmus paper with you. How will you identify which is

which.

6. A student wants to make the salt potassium nitrate. Which two substances should the

student use? Choose two answers.

a)Water b)hydrochloric acid c)potassium hydroxide

d)potassium chloride e) nitric acid.

7. A student wants to make the salt, sodium sulphate. Which two substances should the

student use? Choose two answers

a)Sodium chloride b)sodium hydroxide c)hydrochloric acidd)Water e)sulphuric acid

8. Acids and alkalis can be dangerous substances. You must be careful when you use them.

Design a warning poster for your laboratory.

9. Geologists are scientists who study rocks.

One common rock is called limestone. Limestone contains the mineral calcium carbonate.

Many geologists carry bottles of hydrochloric acid. If they think a rock may be limestone,

they will test it by placing a couple of drops of hydrochloric acid on the rock. If rock fizzes,

the geologists know that the rock is limestone.

(i) Write the word equation between calcium carbonate and hydrochloric acid.

(ii) Why does the limestone fizz when hydrochloric acid is dropped onto it?

(iii) The formula of calcium carbonate is CaCO3. How many different elements are

represented by this formula?

(iv) How will you confirm the gas evolved ?

10. Recently, a well know personality, Mr varun Gandhi married Ms Yamini Roy Chowdhury In

the wedding, she wore a silk asree, which belonged to her grand mother-in-Law, late Mrs.

Indira Gandhi. When Rohini read this news, she wondered how a saree which was 100

years old, could still be fit enough to be worn. Can you help Ragini to get the answer to this

question?