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A polar covalent bond occurs between atoms that have a significant difference in electronegativity. Electronegativity is an atom's ability to attract shared electrons towards itself. Due to this difference, the bonding electron pair (the electrons involved in the bond) spends more time closer to the more electronegative atom. This results in an unequal sharing of the electron pair, creating a partial negative charge (?−) on the more electronegative atom and a partial positive charge (?+) on the less electronegative atom. B. equal sharing of electron pair: This describes a nonpolar covalent bond, which typically occurs between atoms of the same element (e.g., in O\(_2\) or H\(_2\)) where the electronegativity difference is zero or negligible. C. equal sharing of electron lone pair: A lone pair (or unshared pair) is a pair of valence electrons that is not involved in bonding. The concept of "sharing" applies to bonding pairs. D. unequal sharing of electron lone pair: Lone pairs are associated with a single atom and are not shared between atoms in the context of a bond, so this option is chemically inaccurate in describing the bond itself. The correct option is A. unequal sharing of electron pair.

The cell notation convention places the anode on the left and the cathode on the right, separated by a double vertical line representing the salt bridge. A single vertical line represents a phase boundary (solid|aqueous). The reaction involves: Oxidation (anode, left side): Mg is oxidized to Mg²⁺ Mg → Mg\(^{2+}\) + 2e\(^-\). This is represented as Mg l Mg\(^{2+}\) Reduction (cathode, right side): Pb²⁺ is reduced to Pb, Pb\(^{2+}\) + 2e\(^-\) → Pb . This is represented as Pb\(^{2+}\) l Pb The complete notation is Mg l Mg\(^{2+}\) ll Pb\(^{2+}\) l Pb

According to Graham's Law of Diffusion, the rate at which a gas diffuses is inversely proportional to the square root of its molar mass. Therefore, gases with lower molar masses diffuse faster than those with higher molar masses. For the rate of diffusion to increase, the molar masses of the gases must decrease in the sequence listed. The molar masses for the gases in option B are calculated using the provided atomic weights (H=1, O=16, N=14, S=32): SO\(_2\)= 32 + (16 x 2) = 64 g/mol O\(_2\)= 16 x 2 =32 g/mol NH\(_3\) = 14 + (1 x 3) = 17 g/mol H\(_2\) = 1 x 2 = 2 g/mol The order of molar masses is 64 g/mol > 32 g/mol > 17 g/mol > 2 g/mol. Since the molar masses decrease in this sequence, the rate of diffusion increases. The correct arrangement of gases in the order of increasing rate of diffusion is B.

The solution with a pH of 8.0 is likely to turn red moist litmus paper blue, which corresponds to option B. Litmus paper is an indicator used to test for acidity or basicity: Acids (pH below 7) turn blue litmus paper red. The solutions with pH 2.5 and 3.5 are acidic. Bases (pH above 7, or alkaline) turn red litmus paper blue. The solution with pH 8.0 is basic. Neutral solutions (pH exactly 7.0) cause no color change in either red or blue litmus paper. Bases turn red litmus paper blue.Therefore, only the basic solution (pH 8.0) will turn red litmus paper blue.

Rusting is the specific term for the corrosion of iron (and its alloys like steel) that occurs when it reacts with oxygen and moisture in the air to form a reddish-brown, flaky substance called rust (hydrated iron(III) oxide). This is an electrochemical and oxidation process that deteriorates the metal. B. Burning is a combustion process involving rapid reaction with oxygen, usually producing heat and light, and forming different products (ashes, smoke, etc.), not the slow oxidation that results in rust. C. Galvanizing is a method of rust prevention, where a protective coating of zinc is applied to the iron, not the process of corrosion itself. D. Alloying is the process of mixing iron with other metals (like chromium and nickel to make stainless steel) to create a material that is more resistant to corrosion, not the corrosion process itself. The correct answer is rusting - option A

Solubility is expressed as the mass of solute per 100g of solvent. It can be expressed mathematically below as: Solubility = \(\frac{mass of solute}{mass of solvent}\) x \(\frac{100}{1}\) = \(\frac{mass of salt}{mass of water}\) x \(\frac{100}{1}\) Mass of salt = 2g Mass of water = Mass of solution - mass of salt = 12.5 - 2 = 10.5g Solubility = \(\frac{2}{10.5}\) x \(\frac{100}{1}\) = 19.0476 = 19.05 g

Propane, C\(_3\)H\(_8\) reacting with chlorine ((Cl\(_2\)) in sunlight is a free radical substitution reaction, also known as photochemical chlorination, where sunlight (UV light) provides energy to break the \(Cl-Cl\) bond, allowing chlorine atoms to replace hydrogen atoms on the propane molecule, forming chloropropanes and hydrogen chloride (HCl).

During the electrolysis of brine (sodium chloride solution), hydrogen gas (\(H_{2}\)) is produced at the cathode (negative electrode) because water molecules are more easily reduced than sodium ions (\(Na^{+}\)), forming hydrogen gas and hydroxide ions (\(OH^{-}\)). This process also generates sodium hydroxide (caustic soda) and chlorine gas at the anode, making it a crucial industrial process.

In the Orsat apparatus for flue gas analysis, ammoniacal cuprous chloride, CuCl\(_2\) is specifically used to absorb CO. The CO acts as a Lewis base and forms a soluble coordination complex or adduct with the copper(I) ions. A. \(\text{H}_{2}\) (Hydrogen) and C. \(\text{N}_{2}\) (Nitrogen) are generally unreactive with the solution and remain after the absorption process. These are typically determined by difference in a gas analysis experiment. D. \(\text{CO}_{2}\) (Carbon dioxide) is absorbed by a different solution, typically an alkaline solution like potassium hydroxide (\(\text{KOH}\)), in the Orsat apparatus.

Water exists as a liquid at room temperature primarily due to the presence of strong hydrogen bonds between adjacent water molecules. Hydrogen bonds are a strong type of intermolecular force (force between molecules) that cause water molecules to attract each other and resist separation into a gas phase at typical room temperatures. A. electrovalent bond (ionic bond) is a strong force that exists between ions, like in table salt (NaCl), not within or between water molecules. Water is a polar covalent compound. B. covalent bond is the strong intramolecular force that holds the hydrogen and oxygen atoms together within a single water molecule (\(\text{H}_{2}\text{O}\)). The existence of the molecule itself depends on the covalent bonds, but the liquid state (how molecules interact with each other) is due to the intermolecular hydrogen bonds. C. van der waals forces are weaker intermolecular forces present in all molecules. While present, they are much weaker than hydrogen bonds. If only van der Waals forces were present, water would be a gas at room temperature, similar to other hydrides like hydrogen sulfide (\(\text{H}_{2}\text{S}\)).

Reforming, specifically catalytic reforming, is a petroleum refining process used to convert low-octane, straight-chain or cyclic hydrocarbons into high-octane aromatic hydrocarbons. This process improves the quality of gasoline (petrol) and involves dehydrocyclization (cyclization and dehydrogenation). Cyclohexane (\(\text{C}_{6}\text{H}_{12}\)) is a cycloalkane that is converted into the aromatic compound benzene (\(\text{C}_{6}\text{H}_{6}\)) during this process, with the release of hydrogen gas (\(\text{H}_{2}\)). This is a key example of a reforming reaction.The general reaction is: \(\text{C}_{6}\text{H}_{12}\rightarrow \text{C}_{6}\text{H}_{6}+3\text{H}_{2}\). A. hexene to hexane is a hydrogenation reaction (addition of hydrogen to an alkene to form an alkane), not reforming. Reforming typically involves dehydrogenation (removal of hydrogen) and cyclization. C. hexane to carbon(IV)oxide and water vapour is the complete combustion of hexane, which produces energy but is not a petroleum refining process for product reformation. D. hexane to butane and ethane is an example of cracking, a process that breaks down larger hydrocarbons into smaller, more valuable ones, which is distinct from reforming. The correct answer is option B

Carbon(II)oxide, (CO), is primarily a product of the incomplete combustion of carbon-containing fuels such as natural gas, coal, wood, and oil. When there is an inadequate supply of oxygen during burning, CO is produced instead of the less harmful carbon dioxide (CO₂). A. photochemical smog is a type of air pollution resulting from the reaction of sunlight with nitrogen oxides and volatile organic compounds; carbon monoxide is involved in the complex cycles of reactions, but it is a primary pollutant produced by combustion, not the source of the smog itself. The primary components of photochemical smog are secondary pollutants like ozone and peroxyacetyl nitrate (PAN). B. respiration is a natural process in living organisms that produces carbon dioxide (CO₂) as a byproduct, not carbon monoxide (CO). CO₂ is an essential component of the carbon cycle and not typically considered an air pollutant in the same toxicological sense as CO (though it is a major greenhouse gas). D. decomposition of sewage involves biological processes that can produce various gases, such as methane (CH₄) or hydrogen sulfide, but not significant amounts of carbon monoxide as an air pollutant. The correct option is C. combustion of fuel.

According to Le Chatelier's principle, changes in pressure only affect the position of equilibrium in gaseous reactions if there is a difference in the total number of moles of gas between the reactant and product sides of the balanced chemical equation. In the scenario described, there is "no change in volume in a gaseous reaction," which implies that the total number of moles of gaseous reactants is equal to the total number of moles of gaseous products. For example, H\(_2\)\(_{(g)}\) + I\(_2\)\(_{(g)}\) ⇌ 2HI\(_{(g)}\). When the number of moles of gas is the same on both sides, both the forward and backward reaction rates increase or decrease equally in response to a pressure change, so the equilibrium position remains unchanged.

Sodium chloride (\(\text{NaCl}\)) is a salt formed from the neutralization reaction of a strong acid (hydrochloric acid, \(\text{HCl}\)) and a strong base (sodium hydroxide, \(\text{NaOH}\)). When it dissolves in water, neither the sodium ions nor the chloride ions undergo significant hydrolysis (reaction with water). As a result, the concentrations of \(\text{H}^{+}\) and \(\text{OH}^{-}\) ions in the water remain essentially unchanged, and the solution maintains a neutral pH of approximately 7.

The spontaneity of a reaction is determined by the Gibbs free energy change (\(\Delta G\)), given by the equation:\(\Delta G=\Delta H-T\Delta S\)For a reaction to be spontaneous, \(\Delta G\) must be negative (\(\Delta G<0\)). For the given reaction: Entropy Change (\(\Delta S\)): The reaction involves the conversion of one mole of gas into one mole of solid and one mole of gas. The formation of a highly ordered solid from a less ordered gas results in a decrease in entropy, so \(\Delta S\) is negative (\(\Delta S<0\)).Enthalpy Change (\(\Delta H\)): Since the entropy change is negative, the term \(-T\Delta S\) is positive. For \(\Delta G\) to be negative (spontaneous), the \(\Delta H\) term must be sufficiently negative to overcome the positive \(-T\Delta S\) term. Therefore, the reaction must be exothermic, meaning \(\Delta H\) is negative (\(\Delta H<0\)). Therefore, for this specific reaction to be spontaneous, the enthalpy change (\(\Delta H\)) must be negative.