CLASS 10
SCIENCE MOST
IMPORTANT
QUESTIONS
CHAPTERWISE
Gajendra singh lodhi
, PRASHANT KIRAD
SCIENCE
TOP 5 QUESTIONS
Chemical Reactions and Equations
1. Solid calcium oxide was taken in a container and water was added
slowly to it. (CBSE 2013, 2019)
(a) Write the observations.
(b) Write the chemical formula of the product formed.
10
2.What change in color is observed when white silver chloride is
left exposed to sunlight? State the type of chemical reaction in
&
this change. (CBSE 2014, 2019, 2023)
9
B
3.Write the chemical equation of the reaction in which the following
U
PH
changes take place with an example of each. (CBSE 2023, 2015)
(a) Change in color (b) Change in temperature
EX
4. In the electrolysis of water, (CBSE 2020, 2013, SP-2018)
A. Name of the gases liberated at anode & cathode.
B. Why is it that the volume of gas collected on one electrode is
two times that on the other electrode?
C. What would happen if dilute H2 S04 is not added to water?
5. A shining metal ‘M’ on burning gives a dazzling white flame &
changes to a white powder ‘N’. (CBSE 2020, 2022)
A. Identify ‘M’ & ‘N’.
B. Represent the above reaction in the form of a balanced chemical
equation.
C. Does ‘M’ undergo oxidation or reduction in this reaction? Justify.
, PRASHANT KIRAD
SCIENCE
Acids, Bases and Salts
1. List the important products of the chlor-alkali process. Write one
important use of each. (CBSE 2020, 2023)
2. (a) Identify the acid and the base whose combination forms the
common salt that you use in your food. Write its chemical
formula and chemical name of the salt.
(b) What is rock salt?
(c) Mention its color and the reason due to which it has this colour.
(CBSE 2019, 2013)
3.Write the chemical equations when zinc granules react with:
(a) Sulphuric acid (b) Hydrochloric acid10
&
(CBSE 2014, 2020)
9
B
4. How is sodium hydroxide produced? Write the balanced chemical
U
equation also. Why is this process called the chlor-alkali process?
PH
In this process name the products given off at:
(a) anode
EX
(b) cathode. (CBSE 2022, 2015)
5. Give the reasons for the following:
(i) Only one half of water molecule is shown in the formula of
plaster of Paris. (CBSE 2020, CBSE SP - 2017)
2 4
, PRASHANT KIRAD
SCIENCE
Metals and Non-Metals
1. Why do ionic compounds conduct electricity in molten state and not
in solid state? (CBSE 2014, 2023)
2. The reaction of metal X with Fe 2O3 is highly exothermic and is used
to join railway tracks. Identify metal X. Write the chemical
equation for the reaction. (CBSE 2016, 2023)
3. Zinc is a metal found in the middle of the activity series of metals.
In nature, it is found as a carbonate ore, ZnCO 3 . Mention the steps
carried out for extraction from the ore. (CBSE 2023, 2013)
10
4. Differentiate between roasting and calcination giving chemical
equations for each. (CBSE 2013, 2023)
&
9
5. Why are copper vessels corroded with a green coating in the rainy
B
season? (CBSE 2015, 2016, 2019)
U
PH
EX
4
2 4
SCIENCE MOST
IMPORTANT
QUESTIONS
CHAPTERWISE
Gajendra singh lodhi
, PRASHANT KIRAD
SCIENCE
TOP 5 QUESTIONS
Chemical Reactions and Equations
1. Solid calcium oxide was taken in a container and water was added
slowly to it. (CBSE 2013, 2019)
(a) Write the observations.
(b) Write the chemical formula of the product formed.
10
2.What change in color is observed when white silver chloride is
left exposed to sunlight? State the type of chemical reaction in
&
this change. (CBSE 2014, 2019, 2023)
9
B
3.Write the chemical equation of the reaction in which the following
U
PH
changes take place with an example of each. (CBSE 2023, 2015)
(a) Change in color (b) Change in temperature
EX
4. In the electrolysis of water, (CBSE 2020, 2013, SP-2018)
A. Name of the gases liberated at anode & cathode.
B. Why is it that the volume of gas collected on one electrode is
two times that on the other electrode?
C. What would happen if dilute H2 S04 is not added to water?
5. A shining metal ‘M’ on burning gives a dazzling white flame &
changes to a white powder ‘N’. (CBSE 2020, 2022)
A. Identify ‘M’ & ‘N’.
B. Represent the above reaction in the form of a balanced chemical
equation.
C. Does ‘M’ undergo oxidation or reduction in this reaction? Justify.
, PRASHANT KIRAD
SCIENCE
Acids, Bases and Salts
1. List the important products of the chlor-alkali process. Write one
important use of each. (CBSE 2020, 2023)
2. (a) Identify the acid and the base whose combination forms the
common salt that you use in your food. Write its chemical
formula and chemical name of the salt.
(b) What is rock salt?
(c) Mention its color and the reason due to which it has this colour.
(CBSE 2019, 2013)
3.Write the chemical equations when zinc granules react with:
(a) Sulphuric acid (b) Hydrochloric acid10
&
(CBSE 2014, 2020)
9
B
4. How is sodium hydroxide produced? Write the balanced chemical
U
equation also. Why is this process called the chlor-alkali process?
PH
In this process name the products given off at:
(a) anode
EX
(b) cathode. (CBSE 2022, 2015)
5. Give the reasons for the following:
(i) Only one half of water molecule is shown in the formula of
plaster of Paris. (CBSE 2020, CBSE SP - 2017)
2 4
, PRASHANT KIRAD
SCIENCE
Metals and Non-Metals
1. Why do ionic compounds conduct electricity in molten state and not
in solid state? (CBSE 2014, 2023)
2. The reaction of metal X with Fe 2O3 is highly exothermic and is used
to join railway tracks. Identify metal X. Write the chemical
equation for the reaction. (CBSE 2016, 2023)
3. Zinc is a metal found in the middle of the activity series of metals.
In nature, it is found as a carbonate ore, ZnCO 3 . Mention the steps
carried out for extraction from the ore. (CBSE 2023, 2013)
10
4. Differentiate between roasting and calcination giving chemical
equations for each. (CBSE 2013, 2023)
&
9
5. Why are copper vessels corroded with a green coating in the rainy
B
season? (CBSE 2015, 2016, 2019)
U
PH
EX
4
2 4
