3 Marks Question

Question 13 Marks

One day Rahul's mother after taking meal felt pain and irritation in her stomach at that time his father was out of station. Rahul remembered his teacher's statement and gave his mother some baking soda solution which gave her a relief from pain and irritation in stomach.
Read the above passage and answer the following questions
(i) Which information given by Rahul's teacher, that helped him to select the baking soda as remedy?
(ii) Why did he select baking soda as a cure?
(iii) What values are shown by Rahul?

Answer

self

View full question & answer→

Question 23 Marks

Using the knowledge of acids and bases, write a secret message with the help of lemon juice and China rose soluiton. Explain how it works?

Answer

self
<strong>Hint</strong> Prepare a solution of lemon juice. Use this solution to write a message on a sheet of white paper with a cotton bud. Rub China rose solution over the message.

View full question & answer→

Question 33 Marks

Three test tubes A, B and C are taken as shown in figure below. Red litmus paper was dipped in all three test tubes to test which solution is basic in nature. Identify in which test tube the red litmus paper will change its colour to blue?

Answer

self

View full question & answer→

Question 43 Marks

A student took some dilute hydrochloric acid in a flask, added a few drops of phenolphthalein and mixed it gently. After that the student added sodium hydroxide drop by drop to this colourless solution and continued until he saw some change in the colour of the solution.
(i) Name the type of reaction that the experiment demonstrates.
(ii) Complete the following word equation for the simple acid-base reaction that took place in the abvoe experiment.
Sodium hydroxide + Hydrochloric acid → _________________
(iii) Describe and explain the colour of the solution when sodium hydroxide was added.

Answer

self

View full question & answer→

Question 53 Marks

Explain why
(a) an antacid tablet is taken when you suffer from acidity?
(b) calamine solution is applied on the skin, when an ant bites?
(c) factory waste is neutralised before disposing it into the water bodies?

Answer

(a) We take an antacid tablet such as milk of magnesia to neutralise the excessive acid released in stomach during acidity.
(b) When an ant bites, it injects the formic acid into the skin. The effect of acid can be neutralised by applying calamine solution that contains zinc carbonate which is a base.
(c) The factory wastes contain acids if they are allowed to flow into the water bodies without neutralising it, the acid can kill fishes and other organisms. The factory wastes are thus neutralised by adding basic substances

View full question & answer→

Question 63 Marks

Dorji has a few bottles of soft drink in his restaurant, But unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink.
How will Dorji decide which drink is to be served to whom?

Answer

Dorji will decide which drink is to be served to whom (customer) by doing the following litmus paper tests.
(i) If the drink turns blue litmus paper to red, then the drink is acidic and hence, will be served to first customer who wants acidic drink.
(ii) If the drink turns red litmus paper to blue, then the drink is basic and hence, will be served to another customer who wants basic drink.
(iii) If the drink shows no change in colour with litmus paper, then it will be neutral drink. Thus, it will be served to third customer.
Since, the soft drinks are edible. Dorji can take the decision by tasting the drinks also. Acidic drinks will be sour to taste, whereas basic drinks will be bitter to taste and neutral drinks will have no taste.

View full question & answer→

Question 73 Marks

The wastes of many factories contain acids. Why is it considered necessary to neutralise them before allowing the wastes to flow into waterbodies?

Answer

The wastes of many factories contain acids, which can harm aquatic plants and animals if released directly into water bodies. Acidic wastes can lower the pH of water, making it unsafe for living organisms. Therefore, it is necessary to neutralise these wastes to protect the environment and maintain the balance of aquatic life.

View full question & answer→

Question 83 Marks

If someone is suffering from the problem of acidity after over eating, which of the following would you suggest as remedy?
Lemon juice, vinegar, baking soda solution.
Give reason for your choice.

Answer

If someone is suffering from the problem of acidity after overeating, a baking soda solution should be suggested as a remedy. This is because baking soda is a base and it neutralizes the excess acid present in the stomach. Lemon juice and vinegar are acids, so they would increase acidity instead of reducing it.

View full question & answer→

Science 3 Marks Question

Test yourself on this topic