Class 10 (Science) - Revision_230223 (All Chapters) 2022-23

The change in colour of the moist litmus paper in the given set up is due to

• (a) i and ii
• (b) Only ii
• (c) Only iii
• (d) Only iv

In the redox reaction:

• (a) MnO2 is reduced to MnCl2 & HCl is oxidized to H2O
• (b) MnO2 is reduced to MnCl2 & HCl is oxidized to Cl2
• (c) MnO2 is oxidized to MnCl2 & HCl is reduced to Cl2
• (d) MnO2 is oxidized to MnCl2 & HCl is reduced to H2O

Which of the following is the correct observation of the reaction shown in the above set up?

• (a) Brown powder of Magnesium oxide is formed.
• (b) Colourless gas which turns lime water milky is evolved.
• (c) Magnesium ribbon burns with brilliant white light.
• (d) Reddish brown gas with a smell of burning Sulphur has evolved.

With the reference to four gases CO2,CO, Cl2 and O2, which one of the options in the table is correct?

• (a)
• (b)
• (c)
• (d)

On placing a copper coin in a test tube containing green ferrous sulphate solution, it will be observed that the ferrous sulphate solution

• (a) turns blue, and a grey substance is deposited on the copper coin.
• (b) turns colourless and a grey substance is deposited on the copper coin.
• (c) turns colourless and a reddish–brown substance is deposited on the copper coin.
• (d) remains green with no change in the copper coin.

Anita added a drop each of diluted acetic acid and diluted hydrochloric acid on pH paper and compared the colors. Which of the following is the correct conclusion?

• (a) pH of acetic acid is more than that of hydrochloric acid.
• (b) pH of acetic acid is less than that of hydrochloric acid.
• (c) Acetic acid dissociates completely in aqueous solution.
• (d) Acetic acid is a strong acid

The formulae of four organic compounds are shown below. Choose the correct option

• (a) A and B are unsaturated hydrocarbons
• (b) C and D are saturated hydrocarbons
• (c) Addition of hydrogen in presence of catalyst changes A to C
• (d) Addition of potassium permanganate changes B to D

In the given transverse section of the leaf identify the layer of cells where maximum photosynthesis occurs

• (a) I, II
• (b) II, III
• (c) III, IV
• (d) I, IV

Observe the experimental setup shown below. Name the chemical indicated as ‘X’ that can absorb the gas which is evolved as a byproduct of respiration.

• (a) NaOH
• (b) KOH
• (c) Ca (OH)2
• (d) K2CO3

If a tall pea plant is crossed with a pure dwarf pea plant then, what percentage of F1 and F2 generation respectively will be tall?

• (a) 25%, 25%
• (b) 50%, 50%
• (c) 75%,100%
• (d) 100%, 75%