Correct Answer: C. CH₃COONa(s)

Correct Answer: D. calcium trioxosilicate (IV)

Explanation

(a) Fused alumina is mixed with cryolite in the electrolytic extraction of aluminium in order to give a solution of lower melting point and density than that to be obtained without the cryolite

(b) AI\(_2\)O\(_{3(s)}\) + 2NaOH\(_{(ag)}\) + 3H\(_2\)O\(_{(l)}\) \(\to\) \(2 NaAl(OH)_{4(aq)}\)

Correct Answer: A. HF

Explanation

(a)(i) 2KNO\(_3\) \(\to\) 2KNO\(_2\) + O\(_2\)

(ii) C\(_{12}\)H\(_{22}\)O\(_{11}\) + 11H\(_2\)O

(b) Two observations include:

(i) gas is given off

(ii) The zinc disappears to form a colourless solution.

Correct Answer: A. hydrogen bonding

Explanation

(a)(i) Acid anhydride means acid without water. e.g. SO\(_2\), CO\(_2\), etc.

(ii) HCI react with metals more electropositive than hydrogen to liberate hydrogen gas.

-HCI reacts with bases or alkali to produce salt and water only.

-They react with trioxocarbonate (IV) and hydrogen trioxocarbonate (IV) to literate carbon (IV) oxide.

(b)(i) H\(_2\)SO\(_4\) can form a neutral salt and also an acid salt while NHO\(_3\) can only form a neutral salt.

(ii) Both copper and iron have low standard electrode potential and only iron reacts with the dilute acid because it is more active than copper

(iii) The zinc dust has larger area of contact for the reaction to take place unlike the zinc granules.

(c)(i) Activation energy in the combined energy which the reactant particles must have in order to react or for a reaction to occur.

(iii) The heat of reaction of the mineral acids with sodium hydroxide is constant because the only change that actually occurs during the reaction is the formation of water molecule which has an approximately constant value of- 57.4 kJmol\(^{-1}\)

(d)(i) Q\(_{(s)}\) has higher entrophy because the molecules of Q\(_{(s)}\) are free to move than that of Q\(_{(s)}\)

(ii) Decrease in temperature will favour the reverse reaction.

Correct Answer: D) (ii) and (iii) only

Explanation

In order to determine which of the given reactions are redox reactions, we need to identify if there is a transfer of electrons between species in each reaction, meaning that one species is reduced (gains electrons) while another is oxidized (loses electrons).

Let's analyze each reaction:

(i) LiOH + CO\(_2\) \(\rightarrow\) Li\(_2\)CO\(_3\) + H\(_2\)O: In this reaction, lithium (Li) in LiOH does not change its oxidation state, and neither does carbon (C) in CO\(_2\). Therefore, this reaction is not a redox reaction.

(ii) 2H\(_2\) + O\(_2\) \(\rightarrow\) 2H\(_2\)O: In this reaction, hydrogen (H) goes from an oxidation state of 0 in H\(_2\) to +1 in H\(_2\)O, while oxygen (O) goes from an oxidation state of 0 in O\(_2\) to -2 in H\(_2\)O. This means that hydrogen is oxidized, and oxygen is reduced, so this reaction is a redox reaction.

(iii) 2Cu + O\(_2\) \(\rightarrow\) 2CuO: In this reaction, copper (Cu) goes from an oxidation state of 0 in Cu to +2 in CuO, while oxygen goes from an oxidation state of 0 in O\(_2\) to -2 in CuO. This means that copper is oxidized, and oxygen is reduced, so this reaction is a redox reaction.

(iv) HCl + AgNO\(_3\) \(\rightarrow\) AgCl + HNO\(_3\): In this reaction, hydrogen (H) and chlorine (Cl) in HCl exchange places with silver (Ag) and nitrate (NO\(_3\) in AgNO\(_3\), but their oxidation states do not change. This is an example of a metathesis reaction, not a redox reaction.

Based on the analysis, the correct answer isOption D, as only reactions (ii) and (iii) are redox reactions.

Correct Answer: B. lron

Correct Answer: A. noble gas