Correct Answer: A. electrostatic attraction

Explanation

(a) - high temperatures / stated temperature of 500\(^o\)C or more

- catalyst

(b) - To prevent corrosion/rusting/tarnishing

- To make them shiny/for decoration purpose/beautify/attractive

- To make surface harder/thicker

- To make more resistant to chemicals

- To make it durable

- To reduce friction/abrasion

(c) (i) Because calcium oxide is basic and hydrogen chloride is acidic ,they will react

to form salt and water.

(ii) - Fused CaCl\(_2\)

- (Conc) H\(_2\)SO\(_4\) (do not accept dil H\(_2\)SO\(_4\))

- Silica gel

- Phosphorus(V) oxide/P\(_2\)O\(_5\)

(d) Conc. HNO\(_3\) is a strong oxidizing agent. It oxidizes pale green Fe\(^{2+}\) ions to yellow Fe\(^{3+}\) ions(1) and itself reduced to nitrogen (IV) oxide.

(e) (i) I. ZnO(s) + H\(_2\)SO\(_{4(aq)}\) \(\to\) ZnSO\(_{4(aq)}\) + H\(_2\)O\(_{(l)}\)

II. ZnO\(_{(s)}\) + 2NaOH\(_{(aq)}\) \(\to\) Na\(_{2}\) Zn(OH)\(_{4 (aq)}\)

OR

ZnO + 2NaOH \(\to\) Na\(_2\)ZnO\(_2\) + H\(_2\)O

(ii) Amphoterism / Amphoteric properties

(f) (i) Same number (17) of protons / same number (17) of electrons/same atomic number

(ii) Difference in mass numbers / different number of neutrons / 35Cl has 18 neutrons and 37Cl has 20 neutrons

(g) - HCl / hydrochloric acid

- O\(_2\) / Oxygen

&nbs

Correct Answer: B) 5g of marble powder at 50°C

Explanation

Marble is a form of calcium carbonate (CaCO₃) and reacts with hydrochloric acid (HCl) to produce calcium chloride (CaCl₂), water (H₂O), and carbon dioxide (CO₂). The reaction can be represented as:

\(CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + CO_2\)

There are several factors that can affect the rate of this reaction, including temperature, concentration, and surface area of the reactants. In the given options, we can see that the surface area and temperature are the variables being manipulated.

Option A and Option D involve marble lumps, which have a smaller surface area compared to marble powder. A smaller surface area means less contact between the reactants, leading to a slower reaction rate.

Option B and Option C involve marble powder, which has a larger surface area compared to marble lumps. A larger surface area allows for more contact between the reactants, leading to a faster reaction rate.

Temperature also plays a role in the reaction rate. As temperature increases, the kinetic energy of the molecules increases, leading to more frequent and energetic collisions between reactants. This results in a faster reaction rate. Option B has a higher temperature (50^oC) compared to Option C (25^oC), and thus will have a faster reaction rate.

Considering both surface area and temperature,Option B: 5g of marble powder at 50^oC is the correct answer, as it has the largest surface area and the highest temperature, resulting in the fastest reaction rate.

Correct Answer: C. it is similar to hydrolysis

Correct Answer: A) 0.5

Correct Answer: C. II and IV only

Explanation

- Ionization behaviour; The atoms of non-metals usually have four to seven valence electrons. They have a great tendency to ionize by accepting electrons to form negative ions.

- Reaction with acids; A metal which is more electro positive than hydrogen readily displaces the hydrogen ion, H+, from an acid.

Correct Answer: B. Ethanol

Correct Answer: C. allotropy

Correct Answer: B. Copper (ii) carbonate

Correct Answer: A. S^2?