Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

1.	Prove that : cotθ-tanθ=2cos2θ-1/sinθcosθ
Answer» R.H.S. Hence Proved.

Prove that : cotθ-tanθ=2cos2θ-1/sinθcosθ

Answer»

R.H.S. Hence Proved.

Discussion

2.	Two different dice are thrown together. Find the probability that the number obtained.(i) have a sum less than 7.(ii)have a product less than 16.(iii)is a doublet of odd numbers.
Answer» Total number of all possible outcomes = 62= 36 .. . P(a doublet of odd number) = 9/90 = 1/10

Two different dice are thrown together. Find the probability that the number obtained.(i) have a sum less than 7.(ii)have a product less than 16.(iii)is a doublet of odd numbers.

Answer»

Total number of all possible outcomes = 62= 36

.. . P(a doublet of odd number)

= 9/90 = 1/10

Discussion

3.	Write the uses ofSodium chloride.
Answer» UsesSodium chloride • As table salt, an essential constituent of our food. • In the manufacture of Na2CO3, NaOH, Cl2, etc. • For salting out soap, and organic dyes. • In freezing mixtures. • In tanning and textile industries. • As a preservative for fish, meat, butter etc.

Write the uses ofSodium chloride.

Answer»

UsesSodium chloride

• As table salt, an essential constituent of our food.

• In the manufacture of Na2CO3, NaOH, Cl2, etc.

• For salting out soap, and organic dyes.

• In freezing mixtures.

• In tanning and textile industries.

• As a preservative for fish, meat, butter etc.

Discussion

4.	What will happen if heating is not controlled while preparing Plaster of Paris from gypsum?
Answer» It may be noted that the temperature should be controlled carefully. It should not be allowed to rise above 152°C (425K) because, if whole of the water is lost then anhydrous calcium sulphate is produced, which is called dead burnt plaster and it does not have the properties of Plaster of Paris.

Discussion

5.	Explain how pH change in the river water can endanger the lives of aquatic animals.
Answer» Living organisms can survive only in a narrow range of pH change. When pH of rain water is less than 5.6, it is called acid rain. When acid rain flows into the rivers, it lowers the pH of the river water. The survival of aquatic life in such rivers becomes difficult.

Discussion

6.	What are the two main ways in which common salt (sodium chloride) occurs in nature? How is common salt obtained from sea water? Explain
Answer» Salt exists in two forms in nature i.e. in sea water and in the form of Halite a mineral rock of common salt. Common salt can be prepared by evaporation of sea water. Sea water is collected in division of land and it is allowed to evaporate under sunlight. Water is evaporated leaving behind mixtures of salt, form which common salt is separated by dissolving it in suitable reagent and then, recrystallizing salt from the solution.

Discussion

Explore topic-wise InterviewSolutions in .

Prove that : cotθ-tanθ=2cos2θ-1/sinθcosθ

Two different dice are thrown together. Find the probability that the number obtained.(i) have a sum less than 7.(ii)have a product less than 16.(iii)is a doublet of odd numbers.

Write the uses ofSodium chloride.

What will happen if heating is not controlled while preparing Plaster of Paris from gypsum?

Explain how pH change in the river water can endanger the lives of aquatic animals.

What are the two main ways in which common salt (sodium chloride) occurs in nature? How is common salt obtained from sea water? Explain