Some basic concepts of chemistry practice · Mixed difficulty

Option C (Formality) is correct because formality is used to express the concentration of ionic compounds (electrolytes) in solution, as it considers the formula weight of the substance regardless of its degree of dissociation.

Option A (Four) is correct because Avogadro's number is approximately 6.022 × 10²³, which has four significant figures (6, 0, 2, and 2).

Option C is correct because the mole fraction ratio of solute to solvent is the same as the ratio of their moles.

Option D (All of these) is correct because the equivalent weight of a substance is the weight that combines with or displaces 8 parts of oxygen, 1 part of hydrogen, or 35.5 parts of chlorine.

Option B (40,30) is correct. By setting up a system of equations based on the given weights and moles, we can solve for the atomic weights of X and Y.

Option D (188) is the correct answer. The equivalent mass is related to the atomic mass and valency, and this allows us to calculate the molecular mass of the metal nitrate.

Option D (None of the above) is correct because dilution only changes the concentration (normality or molarity), not the number of equivalents or moles of solute.

Option C (50) is correct because in the number 50, the zero is significant as it is a trailing zero after a non-zero digit.

Option A (18.6) is correct because the equivalent weight is calculated by dividing the molar mass of iron by its valency change.

Option D (${\mathrm{C}_3}{\mathrm{H}_6}{\mathrm{O}_3}$) is correct. The molecular formula is a multiple of the empirical formula, and this multiple is determined by the vapor density.

Option C (2, 5 and 16) is correct because balancing the redox reaction requires 2 moles of permanganate, 5 moles of oxalate, and 16 moles of hydrogen ions.

Option B (23.8 mL) is correct because it is the volume of K2Cr2O7 solution required to oxidize 0.81 g of H2S, based on stoichiometry and normality.

Option D is correct because litre is not a base SI unit, but a derived unit for volume.

Option A (17/22) is correct because it represents the stoichiometric mass ratio of NH3 to CO2 required for complete reaction.

Option C is correct because the empirical formula represents the simplest whole-number ratio of atoms in a compound.

Option D ($2.87 \times 10^{-10} \mathrm{~m}; 1.515 \times 10^{-5} \mathrm{~s}; 2.5365 \times 10^{-2} \mathrm{~kg}$) is the correct conversion of the given values into basic units.

Option A is correct because specific gravity is the ratio of the density of a substance to the density of a reference substance (usually water), which can be represented as the weight of 1 mL of the solution.

Option A (30.4 g) is correct because it is the correct mass of FeSO4 oxidized based on the stoichiometry of the reaction with KMnO4.

Option A (Assertion is true, Reason is true and Reason is correct explanation for Assertion) is correct because at very dilute concentrations, the density of the solution approaches the density of water (1 g/cm³), making molarity and molality nearly equal.

Option A is correct because the ratio of the volume of KMnO4 to the volume of Ba(OH)2 consumed is 1:1.

Option A ($A = E \times n$) is correct because the atomic weight (A) is equal to the equivalent weight (E) multiplied by the valence (n).

Option C (0.18 M) is correct. The molarity of the diluted solution is calculated using the dilution formula: $M_1V_1 = M_2V_2$.

Option D (56.0 litre) is correct because the reaction of 2 moles of $KMnO_4$ with HCl liberates 5 moles of $Cl_2$, which corresponds to 56.0 L at NTP for 1 mole of $KMnO_4$.

Option C (0.0177) is correct. The mole fraction of the solute in a 1.00 molal aqueous solution is calculated by considering the moles of solute and solvent.

Option D ($1.66 \times 10^{-27} \mathrm{~kg}$) is correct because one atomic mass unit (amu) is defined as 1/12th the mass of a carbon-12 atom, which is approximately $1.66 \times 10^{-27} \mathrm{~kg}$.

Option A (64) is correct because the equivalent mass of SO2 is 32 and twice that value is 64.

Option A (Acharya Kanda) is correct because Acharya Kanda was one of the earliest proponents of atomic theory in ancient India.

Option B (0.05) is correct. By calculating the molar mass of X and using the given information, we can determine the number of moles in 5g of ${XY}_2$.

The correct answer is C (Both Assertion and Reason are correct and Reason is correct explanation of Assertion) because the actual yield is often less than the theoretical yield due to impure reactants and side reactions.

Option B (6.02 × 10²³) is correct because N/n represents Avogadro's number, which is approximately 6.02 × 10²³.