chemistry UNIT TEST

Which one of the following reaction represents calcination?

• (a) 2Zn + O₂ → 2ZnO

• (b) 2ZnS + 3O₂ → 2ZnO + 2SO₂

• (c) MgCO₃ → MgO + CO₂

• (d) Both (a) and (c)

Bauxite has the composition ………………

• (a) Al₂O₃

• (b) Al₂O₃.nH₂O

• (c) Fe₂O₃.2H₂O

• (d) None of these

Which of the metal is extracted by Hall-Herold process?

• (a) Al

• (b) Ni

• (c) Cu

• (d) Zn

Which metal is used for making coins and ornaments along with gold and other metals?

• (a) Zn

• (b) Al

• (c) Cu

• (d) Fe

Which of the following is used for concentrating ore in metallurgy?

• (a) Leaching

• (b) Roasting

• (c) Froth floatation

• (d) Both (a) and (c)

Which of the following reduction is not thermodynamically feasible?

• (a) Cr₂O₃ → Al₂O₃ + 2Cr

• (b) Al₂O₃ → Cr₂O₃ + 2Al

• (c) 3TiO₂ + 4Al → 2Al₂O₃ + 2Al

• (d) none of these

Heating mixture of Cu₂O and Cu₂S will give ……………

• (a) Cu + SO₂

• (b) Cu + SO₃

• (c) CuO + CuS

• (d) Cu₂SO₃

The ore which contains both copper and iron ……………

• (a) Cuprite

• (b) Haematite

• (c) Copper pyrite

• (d) Malachite

Depressing agents used to separate ZnS from PbS is ……………

• (a) NaCN

• (b) NaCl

• (c) NaNO₃

• (d) NaNO₂

Which of the following plot gives Ellingham diagram?

• (a) ∆S Vs T

• (b) ∆G° Vs T

• (c) ∆G° Vs

• (d) ∆G Vs T