SolveIt is under development
SolveItNCERT · CBSE · NEET

NCERT Exemplar · Class 10 Science Metals and Non-metals

65 questions · 65 still being checked

Multiple Choice Questions 11–20 (part 2 of 7)

  1. Exercise 11

    Which of the following metals exist in their native state in nature?
    (i)
    Cu
    (ii)
    Au
    (iii)
    Zn
    (iv)
    Ag
    (a) (i) and (ii)
    (b) (ii) and (iii)
    (c) (ii) 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
    (c)
    (c) Au and AgAu and Ag sit at the bottom of the activity series, so they resist oxidation and occur free; Zn is found only combined.

  2. Exercise 12

    Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining?
    (i)
    Au
    (ii)
    Cu
    (iii)
    Na
    (iv)
    K
    (a) (i) and (ii)
    (b) (i) and (iii)
    (c) (ii) 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
    (a)
    (a) Au and CuCu and Au are purified by electrolytic refining; Na and K are too reactive and are extracted by electrolysing their molten chlorides.

  3. Exercise 13

    Silver articles become black on prolonged exposure to air. This is due to the formation of
    (a)
    Ag3N\displaystyle \mathrm{Ag}_3 \mathrm{N}
    (b)
    Ag2O\displaystyle \mathrm{Ag}_2 \mathrm{O}
    (c)
    Ag2S\displaystyle \mathrm{Ag}_2 \mathrm{S}
    (d)
    Ag2S\displaystyle \mathrm{Ag}_2 \mathrm{S} and Ag3N\displaystyle \mathrm{Ag}_3 \mathrm{N}

    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) \(\displaystyle \mathrm{Ag_2S}\)Trace \(\displaystyle \mathrm{H_2S}\) in air reacts with the silver surface, laying down a dull black sulphide film. \[2\,\mathrm{Ag} + \mathrm{H_2S} \rightarrow \mathrm{Ag_2S} + \mathrm{H_2}\uparrow \]

  4. Exercise 14

    Galvanisation is a method of protecting iron from rusting by coating with a thin layer of
    (a)
    Gallium
    (b)
    Aluminium
    (c)
    Zinc
    (d)
    Silver

    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) ZincA thin zinc coat is more reactive than the iron beneath, so it oxidises first and also blocks moist air from reaching the metal, protecting it from rusting.

  5. Exercise 15

    Stainless steel is very useful material for our life. In stainless steel, iron is mixed with
    (a)
    Ni and Cr
    (b)
    Cu and Cr
    (c)
    Ni and Cu
    (d)
    Cu and Au

    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) Ni and CrIron alloyed with nickel and chromium gains corrosion resistance and hardness, giving stainless steel its rust-free, durable finish.

  6. Exercise 16

    If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of
    (a)
    CuSO4\displaystyle \mathrm{CuSO}_4
    (b)
    CuCO3\displaystyle \mathrm{CuCO}_3
    (c)
    Cu(NO3)2\displaystyle \mathrm{Cu}\left(\mathrm{NO}_3\right)_2
    (d)
    CuO

    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) \(\displaystyle \mathrm{CuCO_3}\)Moist air's \(\displaystyle \mathrm{CO_2}\) and \(\displaystyle \mathrm{O_2}\) slowly react with the copper surface, laying down a green basic-carbonate film. \[2\,\mathrm{Cu} + \mathrm{H_2O} + \mathrm{CO_2} + \mathrm{O_2} \rightarrow \mathrm{CuCO_3}\cdot\mathrm{Cu(OH)_2} \]

  7. Exercise 17

    Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature?
    (a)
    Na
    (b)
    Fe
    (c)
    Cr
    (d)
    Hg

    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) Hg. \[T_m(\mathrm{Hg}) = -38.8^\circ\mathrm{C} < 25^\circ\mathrm{C} = T_{\text{room}} \] Mercury alone melts below room temperature; Na, Fe and Cr stay solid at $\displaystyle 25$°C.

  8. Exercise 18

    Which of the following metals are obtained by electrolysis of their chlorides in molten state?
    (i)
    Na
    (ii)
    Ca
    (iii)
    Fe
    (iv)
    Cu
    (a) (i) and (iv)
    (b) (iii) and (iv)
    (c) (i) and (iii)
    (d) (i) and (ii)

    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) (i) and (ii) — Na, Ca. \[2\mathrm{NaCl} \xrightarrow[\text{molten}]{\text{electrolysis}} 2\mathrm{Na} + \mathrm{Cl_2} \] \[\mathrm{CaCl_2} \xrightarrow[\text{molten}]{\text{electrolysis}} \mathrm{Ca} + \mathrm{Cl_2} \] Na and Ca are high in the reactivity series, so their molten chlorides are electrolysed; Fe and Cu are reduced by other methods.

  9. Exercise 19

    Generally, non-metals are not lustrous. Which of the following non-metal is lustrous?
    (a)
    Sulphur
    (b)
    Oxygen
    (c)
    Nitrogen
    (d)
    Iodine

    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) Iodine. Iodine crystals show a metallic-looking lustre despite being a non-metal; sulphur, oxygen and nitrogen are dull.

  10. Exercise 20

    Which one of the following four metals would be displaced from the solution of its salts by other three metals?
    (a)
    Mg
    (b)
    Ag
    (c)
    Zn
    (d)
    Cu

    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)
    Hint— Reactivity series \(\displaystyle \mathrm{Mg}>\mathrm{Zn}>\mathrm{Cu}>\mathrm{Ag}\)
    (b) Ag. \[\mathrm{Mg} > \mathrm{Zn} > \mathrm{Cu} > \mathrm{Ag} \quad (\text{reactivity series}) \] \[\mathrm{Cu} + 2\mathrm{AgNO_3} \rightarrow \mathrm{Cu(NO_3)_2} + 2\mathrm{Ag} \] Ag sits lowest in the series, so each of the other three displaces it from its salt solution.