MCQs Olmpiad NSO Science

Q1. A teacher gave two test tubes to the students, one containing water and the other containing sodium hydroxide. She asked them to identify the test tube containing sodium hydroxide solution. Which one of the following can be used for the identification ?

1. Blue litmus
2. Red litmus
3. Sodium carbonate solution
4. Dilute hydrochloric acid

Answer: B

Q2. The pH of a solution is 7. How can you increase its pH ?

1. By adding a small amount of acid
2. By adding a small amount of base
3. By adding a small amount of salt
4. By passing carbon dioxide gas through it

Answer: B

Q3. The oxide of a metal M is water soluble. When a blue litmus strip was dipped in this solution, it did not undergo any change in colour, but it changed the colour of phenolphthalein. What is the nature of the oxide ?

1. Acidic
2. Basic
3. Neutral
4. Amphoteric

Answer: B

Q4. When the stopper of a bottle containing colourless liquid was removed, the bottle gave a smell like that of vinegar. The liquid in the bottle could be :

1. Hydrochloric acid solution
2. Sodium hydroxide solution
3. Saturated sodium bicarbonate solution
4. Acetic acid solution

Answer: C

Q5. The pH of three solutions X, Y and Z is 6, 4 and 8 respectively. Which of the following is the correct order of acidic strength ?

1. X > Y > Z
2. Z > Y > X
3. Y > X > Z
4. Z > X > Y

Answer: C

Q6. Acetic acid was added to a solid X kept in a test tube. A colourless and odourless gas was evolved. The gas was passed through lime water which turned milky. It was concluded that :

1. Solid X is sodium hydroxide and the gas evolved is H 2
2. Solid X is sodium bicarbonate and the gas evolved is CO 2
3. Solid X is sodium acetate and the gas evolved is CO 2
4. Solid X is sodium chloride and the gas evolved is H 2

Answer: B

Q9. What is Y ?

1. Washing soda
2. Baking soda
3. Bleaching powder
4. Gypsum

Answer: D

Q10. Ratio of water molecules in Y : X is :

1. 4 : 1
2. 2 : 1
3. 1 : 1
4. 1 : 4

Answer: A