SolveIt is under development
SolveItNCERT · CBSE · NEET

NCERT Exemplar · Class 10 Science Chemical Reactions and Equations

44 questions · 44 still being checked

Multiple Choice Questions 1–10 (part 1 of 5)

  1. Exercise 1

    Which of the following is not a physical change?
    (a)
    Boiling of water to give water vapour
    (b)
    Melting of ice to give water
    (c)
    Dissolution of salt in water
    (d)
    Combustion of Liquefied Petroleum Gas (LPG)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (d)
    (d) Combustion of LPG forms new substances (\(\displaystyle \mathrm{CO_2}\), \(\displaystyle \mathrm{H_2O}\)); the other three only change state or dissolve, with nothing new formed.\[2\mathrm{C_4H_{10}(g)} + 13\mathrm{O_2(g)} \rightarrow 8\mathrm{CO_2(g)} + 10\mathrm{H_2O(g)} \]

  2. Exercise 2

    The following reaction is an example of a
    4NH3( g)+5O2( g)→4NO(g)+6H2O(g)\displaystyle 4 \mathrm{NH}_3(\mathrm{~g})+5 \mathrm{O}_2(\mathrm{~g}) \rightarrow 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_2 \mathrm{O}(\mathrm{g})
    (i)
    displacement reaction
    (ii)
    combination reaction
    (iii)
    redox reaction
    (iv)
    neutralisation reaction
    (a) (i) and (iv)
    (b) (ii) and (iii)
    (c) (i) and (iii)
    (d) (iii) and (iv)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (c)
    (c) (i) and (iii). Redox: N is oxidised, O reduced. Two products, so not combination; no acid and base, so not neutralisation. O displaces H from \(\displaystyle \mathrm{NH_3}\) to form \(\displaystyle \mathrm{H_2O}\).\[\mathrm{N}:\ -3\ (\mathrm{NH_3}) \longrightarrow +2\ (\mathrm{NO}) \quad \text{oxidised} \] \[\mathrm{O}:\ 0\ (\mathrm{O_2}) \longrightarrow -2\ (\mathrm{NO},\ \mathrm{H_2O}) \quad \text{reduced} \]

  3. Exercise 3

    Which of the following statements about the given reaction are correct?
    3Fe(s)+4H2O(g)→Fe3O4( s)+4H2( g)\displaystyle 3 \mathrm{Fe}(\mathrm{s})+4 \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \rightarrow \mathrm{Fe}_3 \mathrm{O}_4(\mathrm{~s})+4 \mathrm{H}_2(\mathrm{~g})
    (i)
    Iron metal is getting oxidised
    (ii)
    Water is getting reduced
    (iii)
    Water is acting as reducing agent
    (iv)
    Water is acting as oxidising agent
    (a) (i), (ii) and (iii)
    (b) (iii) and (iv)
    (c) (i), (ii) and (iv)
    (d) (ii) and (iv)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (c)
    Hint— The substance which oxidises the other substances in a chemical reaction is known as an oxidising agent. Likewise, the substance which reduces the other substance in a chemical reaction is known as reducing agent.
    (c) Fe is oxidised (\(\displaystyle 0\) to average \(\displaystyle +\tfrac{8}{3}\) in \(\displaystyle \mathrm{Fe_3O_4}\)); H in water is reduced (\(\displaystyle +1\) to \(\displaystyle 0\)), so water is the oxidising agent, not the reducing agent.\[\mathrm{Fe}:\ 0 \longrightarrow +\tfrac{8}{3}\ (\mathrm{Fe_3O_4}) \quad \text{oxidised} \] \[\mathrm{H}:\ +1\ (\mathrm{H_2O}) \longrightarrow 0\ (\mathrm{H_2}) \quad \text{reduced} \]

  4. Exercise 4

    Which of the following are exothermic processes?
    (i)
    Reaction of water with quick lime
    (ii)
    Dilution of an acid
    (iii)
    Evaporation of water
    (iv)
    Sublimation of camphor (crystals)
    (a) (i) and (ii)
    (b) (ii) and (iii)
    (c) (i) and (iv)
    (d) (iii) and (iv)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (a)
    (a) Slaking of lime and dilution of an acid both release heat; evaporation and sublimation absorb heat to overcome intermolecular forces.\[\mathrm{CaO(s)} + \mathrm{H_2O(l)} \rightarrow \mathrm{Ca(OH)_2(aq)} + \text{heat} \]

  5. Exercise 5

    Three beakers labelled as A, B and C each containing 25\displaystyle 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4\displaystyle \mathrm{CuSO}_4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is(are) correct?
    (i)
    In beakers A and B, exothermic process has occurred.
    (ii)
    In beakers A and B, endothermic process has occurred.
    (iii)
    In beaker C exothermic process has occurred.
    (iv)
    In beaker C endothermic process has occurred.
    (a) (i) only
    (b) (ii) only
    (c) (i) and (iv)
    (d) (ii) and (iii)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (c)
    (c) NaOH and anhydrous \(\displaystyle \mathrm{CuSO_4}\) dissolve exothermically (A, B warm up); NaCl dissolves endothermically (C cools).\[\mathrm{NaOH(s)} \xrightarrow{\mathrm{H_2O}} \mathrm{Na^+(aq)} + \mathrm{OH^-(aq)} + \text{heat} \]

  6. Exercise 6

    A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?
    (a)
    KMnO4\displaystyle \mathrm{KMnO}_4 is an oxidising agent, it oxidises FeSO4\displaystyle \mathrm{FeSO}_4
    (b)
    FeSO4\displaystyle \mathrm{FeSO}_4 acts as an oxidising agent and oxidises KMnO4\displaystyle \mathrm{KMnO}_4
    (c)
    The colour disappears due to dilution; no reaction is involved
    (d)
    KMnO4\displaystyle \mathrm{KMnO}_4 is an unstable compound and decomposes in presence of FeSO4\displaystyle \mathrm{FeSO}_4 to a colourless compound.

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (a)
    (a) \(\displaystyle \mathrm{MnO_4^-}\) is reduced (Mn: \(\displaystyle +7\rightarrow+2\), purple fades to colourless) while \(\displaystyle \mathrm{Fe^{2+}}\) is oxidised to \(\displaystyle \mathrm{Fe^{3+}}\).\[\mathrm{MnO_4^-} + 8\mathrm{H^+} + 5\mathrm{Fe^{2+}} \rightarrow \mathrm{Mn^{2+}} + 4\mathrm{H_2O} + 5\mathrm{Fe^{3+}} \]

  7. Exercise 7

    Which among the following is(are) double displacement reaction(s)?
    (i)
    Pb+CuCl2→PbCl2+Cu\displaystyle \mathrm{Pb}+\mathrm{CuCl}_2 \rightarrow \mathrm{PbCl}_2+\mathrm{Cu}
    (ii)
    Na2SO4+BaCl2→BaSO4+2NaCl\displaystyle \mathrm{Na}_2 \mathrm{SO}_4+\mathrm{BaCl}_2 \rightarrow \mathrm{BaSO}_4+2 \mathrm{NaCl}
    (iii)
    C+O2→CO2\displaystyle \mathrm{C}+\mathrm{O}_2 \rightarrow \mathrm{CO}_2
    (iv)
    CH4+2O2→CO2+2H2O\displaystyle \mathrm{CH}_4+2 \mathrm{O}_2 \rightarrow \mathrm{CO}_2+2 \mathrm{H}_2 \mathrm{O}
    (a) (i) and (iv)
    (b) (ii) only
    (c) (i) and (ii)
    (d) (iii) and (iv)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (b)
    (b) (ii) only.\[\text{(i)}\ \mathrm{Pb + CuCl_2 \rightarrow PbCl_2 + Cu} \quad \text{single displacement} \] \[\text{(ii)}\ \mathrm{Na_2SO_4 + BaCl_2 \rightarrow BaSO_4\downarrow + 2NaCl} \quad \text{double displacement} \] \[\text{(iii)}\ \mathrm{C + O_2 \rightarrow CO_2} \quad \text{combination} \] \[\text{(iv)}\ \mathrm{CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O} \quad \text{combustion} \] Only (ii) exchanges both ion pairs to give a precipitate.

  8. Exercise 8

    Which among the following statement(s) is(are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to
    (i)
    the formation of silver by decomposition of silver chloride
    (ii)
    sublimation of silver chloride
    (iii)
    decomposition of chlorine gas from silver chloride
    (iv)
    oxidation of silver chloride
    (a) (i) only
    (b) (i) and (iii)
    (c) (ii) and (iii)
    (d) (iv) only

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (a)
    (a) (i) only.\[2\mathrm{AgCl} \xrightarrow{\text{sunlight}} 2\mathrm{Ag} + \mathrm{Cl_2} \] Sunlight decomposes \(\displaystyle \mathrm{AgCl}\) into grey silver metal and chlorine gas; it is decomposition, not sublimation or oxidation.

  9. Exercise 9

    Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?
    (i)
    It is an endothermic reaction
    (ii)
    It is an exothermic reaction
    (iii)
    The pH of the resulting solution will be more than seven
    (iv)
    The pH of the resulting solution will be less than seven
    (a) (i) and (ii)
    (b) (ii) and (iii)
    (c) (i) and (iv)
    (d) (iii) and (iv)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (b)
    (b) (ii) and (iii).\[\mathrm{CaO + H_2O \rightarrow Ca(OH)_2} \quad \Delta H < 0 \] Heat is released, so slaking is exothermic; \(\displaystyle \mathrm{Ca(OH)_2}\) is a base, so the lime water formed has \(\displaystyle \mathrm{pH} > 7\).

  10. Exercise 10

    Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved?
    (i)
    Displacement reaction
    (ii)
    Precipitation reaction
    (iii)
    Combination reaction
    (iv)
    Double displacement reaction
    (a) (i) only
    (b) (ii) only
    (c) (iv) only
    (d) (ii) and (iv)

    Matches the book, not yet reviewed

    This working reaches the answer NCERT prints. It has not yet been read through by hand.

    NCERT’s answer
    (d)
    (d) (ii) and (iv).\[\mathrm{BaCl_2 + (NH_4)_2SO_4 \rightarrow BaSO_4\downarrow + 2NH_4Cl} \] Cations swap partners, so it is double displacement, and insoluble \(\displaystyle \mathrm{BaSO_4}\) precipitates out, so it is also a precipitation reaction.