Class 10 Science - Chapter Acids, Bases and Salts NCERT Solutions | Name the substance which on treatment wi

Why does distilled water not conduct electricity, whereas rain water does?

Plaster of Paris should be stored in a moisture-proof container. Explain why?

A solution turns red litmus blue, its pH is likely to be

  (a) 1          (b) 4          (c) 5          (d) 10

Give two important uses of washing soda and baking soda.

Why should curd and sour substances not be kept in brass and copper vessels?

Why do HCl, HNO₃, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?

Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?

Five solutions A,B,C,D and E when tested with universal indicator showed pH as 4,1,11,7 and 9, respectively. Which solution is

(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?

Arrange the pH in increasing order of hydrogen-ion concentration.

A milkman adds a very small amount of baking soda to fresh milk.

   (a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
   (b) Why does this milk take a long time to set as curd?

Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

What is a good source of energy?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?

How does chemical coordination occur in plants?

Why is a normal eye not able to see clearly the objects placed closer than 25 cm?

On what factors does the resistance of a conductor depend?

What were the limitations of Newlands’ Law of Octaves?

The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?

Why is variation beneficial to the species but not necessarily for the individual?

Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

What are the different ways in which glucose is oxidised to provide energy in various organisms?

We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?