X, Y & Z are three metallic atoms in successive order belonging to the same group such that atomic radii of ‘X’ is the smallest. Which of the three atoms is the best reducing agent?

1. X
2. Y
3. Z
4. All three have the same reducing power.

40 cm³ of methane (CH₄) is reacted with 60 cm³ of oxygen. The equation for the reaction is given below:

CH₄ + 2O₂ ⟶ CO₂ + 2H₂O

All volumes are measured at room temperature. What is the total volume of the gases remaining at the end of the reaction?

1. 60 cm³
2. 40 cm³
3. 45 cm³
4. 50 cm³

State the terms for the following:

(a) Undistilled alcohol containing a large amount of methanol.

(b) A salt formed by the partial replacement of the hydroxyl group of a di-acidic or a tri-acidic base by an acid radical.

(c) Organic compounds having the same molecular formula but different structural formula.

(d) The tendency of an atom to attract the shared pair of electrons towards itself when combined in a compound.

(e) The type of covalent bond in which electrons are shared unequally between the combining atoms.

Complete the following sentences by choosing the correct word(s) from the brackets:

(a) …………… solution forms a coloured precipitate with ammonium hydroxide which is soluble in excess of ammonium hydroxide. [Ferrous chloride / Copper nitrate]

(b) Zinc blende is converted to zinc oxide by ……………. [Calcination / Roasting]

(c) …………… conducts electricity by the movement of ions. [Molten iron / Molten sodium chloride]

(d) The reaction that takes place at the anode during the electrolysis of aqueous Sodium argentocyanide with silver electrodes is ……………. [Ag ⟶ Ag⁺ + e^-/ Ag⁺ + e^- ⟶ Ag]

(e) The salt formed when ZnO reacts with hot concentrated NaOH is …………… . [sodium zincate / zinc hydroxide]