Correct Answer: B. ionic

Correct Answer: C. kerosene

Correct Answer: A. strong acid and strong base

Correct Answer: B. crystallization

Correct Answer: B. 1 x 6.02 x10²³

Explanation

(a)(i) I. Anode – Electrode at which oxidation occurs / electron loss

II. Cathode – Electrode at which reduction occurs / electron gain

(ii) I. Cathodic reaction

Na\(^{+_(l)}\) + e\(^{-}\) —> Na\(_{s}\) .

Anodic reaction

2cl\(^{-_(l)}\) --> Cl\(_{2}\) + 2e\(^{-}\)

II. Cathodic reaction

Al\(^{3+}_{(l)}\) + 3\(^{-}\) —> Al.

Anodic reaction

2O\(^{2-}_{l}\) ----> O\(_2\) + 4e\(^{-}\)

(iii) In the extraction of aluminium, Oxygen is produced whereas in the extraction of sodium, chlorine is produced. Chlorine is an environmental pollutant whereas oxygen is not.

(b)(i) The reaction is a redox because both oxidation and reduction occur simultaneously. The oxidation number of Cr changes from +6 (in K\(_2\)Cr\(_2\)O\(_7\)) to +3 (in CrCl\(_3\)). Cr is therefore reduced. The oxidation number of Cl changes from –1 (in HCl) to 0 (in Cl\(_2\)). CI is therefore oxidized.

OR

Removal of hydrogen from HCl is Oxidation. Removal of Oxygen from K\(_2\)Cr\(_2\)O\(_7\) is reduction.

(ii) Reduction Cr\(_2\)O\(_2\)\(^{2-}\) + 14H\(^{+}\) + 6e\(^{-}\) \(\to\) 2Cr\(^{3+}\) + 7H\(_2\)O Oxidation

2Cl\(^{-}\) \(\to\) Cl\(_2\) + 2e\(^{-}\)

(iii) Cr\(_2\)O\(_7\)\(^{2-}\) + 14H\(^{+}\) + 6Cl\(^{-}\) --> 2Cr\(^{3+}\) + 7H\(_2\)O + 3Cl\(_2\)

OR

K\(_2\)Cr\(_2\)O\(_7\) + 14HCl \(\to\) 2KCl + CrCl\(_3\) + H\(_2\)O + CI\(_2\)

(c) Q = I x T

6 x (30 +60) x 60

= 32400C

Al\(^{3+}\) + 3e\(^{-}\) \(\to\) Al\(_{(l)}\)

Correct Answer: D) Q will form an electrovalent bond with S

Explanation

This question is testing your understanding of chemical bonding and electron configurations of different elements. Element P has 6 electrons, Q has 11, R has 15 and S has 16 electrons.

Ionic bonding occurs when an atom loses or gains electrons to achieve a full outer shell. Covalent bonding occurs when atoms share electrons to complete their outer shells. Electrovalent or polar covalent bonding occurs when there is a difference in the electronegativity of the atoms that are bonding.

Since element Q has 11 electrons, it needs one more electron to complete its outer shell and become stable. Element S has 16 electrons, which means it needs to lose two electrons to complete its outer shell. Therefore, element Q will form an electrovalent bond with element S, where Q will gain one electron and S will lose two electrons to form a stable compound.

Option D is the correct answer. Option A cannot be correct because elements P and R have a large difference in the number of electrons, making it unlikely for them to form an ionic bond. Option B is incorrect because both elements R and S are non-metals, making it unlikely for them to form an electrovalent bond. Option C is incorrect because both elements Q and S are non-metals, making it unlikely for them to form a covalent bond.

To learn more about chemical bonding and electron configurations, please read the relevant sections of your recommended textbooks.

Correct Answer: D. sterilization of water

Correct Answer: D. CI2

Correct Answer: D. Pentylethanoate