In this page we have Class 10 Science Acid base and Salts Long Questions( Four Marks questions) . Hope you like them and do not forget to like , social shar
and comment at the end of the page.
1) On passing excess CO2 through lime water, it first turns milky and then becomes colourless. Explain why? Write the chemical reactions.
2) While eating food, you happen to spill some curry on your white shirt. You immediately scrub it with soap. What happens to its yellow colour on scrubbing with soap? Why? What happens to this stain when the shirt is washed with plenty of water?
3) Explain the action of dilute hydrochloric acid on the following with chemical equations:
(a) Magnesium ribbon
(b) Sodium hydroxide
(c) Crushed egg shells
4) What are products formed when an acid reacts with a base? What is the type of reaction? Give one example and name the salt obtained.
5) On adding dilute hydrochloric acid to copper oxide powder, the solution formed is blue – green.
(a) Identify the compound formed which gives blue – green colour to the solution.
(b) Write its balanced chemical equation.
(c) On the basis of above reaction, what should be the nature of copper oxide?
6)Sugandha prepares HCI gas in her school laboratory using certain chemicals. She puts both dry and wet blue litmus papers in contact with the gas.
(i) Name the reagents used by Sugandha to prepare HCI gas.
(ii) State the colour changes observed with the dry and wet blue litmus paper.
(iii) Show the formation of ions when HCI gas combines with water.
7) Hoe the following substances will dissociate to produce ions in their solution?
(a) Hydrochloric acid
(b) Nitric acid
(c) Sulphuric acid
(d) Sodium hydroxide
(e) Potassium hydroxide
(f) Magnesium hydroxide
8) Differentiate between strong electrolytes and weak electrolytes. Mention two examples of each.
9) State reasons for the following:
(a) A tarnished copper vessel begins to shine again rubbed with lemon.
(b)All alkalis are bases but all bases are not alkalis.
(c) Use of a mild base like baking soda on the honey – bee stung area gives relief.
1) (a) State what happens when an acid reacts with a base? Name the reaction and give equation of the reaction involved.
(b) Name one natural source of each of the following acids:
(i) Citric acid
(ii) Oxalic acid
(iii) Lactic acid
(iv) Tartaric acid
(v) Acetic acid
11) A student mixed equal volumes of hydrochloride acid and sodium hydroxide solutions of same concentration.
(i) What would be the pH and colour of pH paper of the resulting solution and why?
(ii) Write the chemical equation of the reaction involved.
12) State the colour change on treating pH paper with the folloing solutions:
sodium hydroxide solution, water, sulphuric acid solution, calcium hydroxide solution. Arrange the following solutions in increasing order of pH.
13) (a) Name the acid produced in our stomach. What happens when there is an excess secretion of acid in the stomach? How can its effect be cured?
(b) Explain how pH change is the cause of tooth decay? How it can be prevented?
(c) What is the ideal soil pH for the growth of plants? Explain with the help of an activity how will you test the pH of a sample of soil collected from your locality?
14) Name one indicator which specifies the various levels of H+ ion concentration.
15) A compound ‘X’ is a constitute of baking powder. It is used as an antacid. When ‘X’ is heated it gives out a gas ‘Y’ which when passed through lime water turns it milky and a salt ‘Z’ is formed which is the main constituent of washing powder. Identify ‘X’, ‘Y’ and ‘Z’. Write balanced chemical equations for the reactions involved.
16) How is Plaster of Paris chemically different from gypsum? How can they be interconverted? Write two uses of Plaster of paris.
17) Write one point of difference between each of the following:
(a) A hydrated salt and an anhydrous salt.
(b) Washing soda and soda ash.
(c) Baking soda and baking powder.
18) On the basis of their pH values, how will you identify neutral, acidic and basic salt solution? How are these salts prepared?
19) Give two uses each of sodium hydroxide, hydrogen and chlorine.
20) When this white powder is mixed with water a hard solid mass is obtained. Write balanced chemical equation for this change.
21) Write name of the compound:
(a) Used for softening hard water.
(b) Used as an antacid.
(c) Which is a component of washing soda.
(d) Which is used as an oxidizing agent in many chemical industries?
22) A gas X reacts with lime water and forms a compound Y which is used as a bleaching agent in chemical industry. Identify X and Y. Give the chemical equation of the reaction involved.