Multiple Choice Questions (MCQ) and Answers on Stoichiometry
Question 1 : The weight fraction of methanol in an aqueous solution is 0.64. The mole fraction of methanol XMsatisfies
- XM < 0.5
- XM = 0.5
- 0.5 < XM < 0.64
- XM ≥ 0.64
Answer : 4
Question 2 : On addition of 1 c.c. of dilute hydrochloric acid (1% concentration) to 80 c.c. of a buffer solution of pH = 4, the pH of the solution becomes
- 1
- 8
- 4
- 2
Answer : 3
Question 3 : Pick out the wrong statement.
- Heat capacity of a diatomic gas is higher than that of a monoatomic gas.
- Equal volumes of Argon and Krypton contain equal number of atoms.
- Total number of molecules contained in 22.4 litres of hydrogen at NTP is 6.023 x 1023.
- The binary mixture of a particular com-positidn in both vapor and liquid state is known as an azeotropic mixture
Answer : 2
Question 4 : 1 kgf/cm2 is not equal to
- 1 torr
- 1 bar
- 10000 mm wc
- 100 KPa = 100 000 N/m2
Answer : 1
Question 5 : The activity co-efficient of a solution, which accounts for the departure of liquid phase from ideal solution behaviour
- measures the elevation in boiling point.
- is not dependent on the temperature.
- is a function of the liquid phase composition.
- measures the depression in freezing point.
Answer : 3
Question 6 : Osmotic pressure of a dilute solution of a non volatile solute in a solvent obeying Raoult’s law is proportional to the
- temperature.
- volume of solution.
- moles of non-volatile solute.
- none of these.
Answer : 1
Question 7 : In case of an unsaturated vapor-gas mixture, the humid volume increases with increase in the
- total pressure.
- absolute humidity at a given temperature.
- both (1) and (2).
- neither (1) nor (2).
Answer : 3
Question 8 : Which of the following is an exothermic reaction ?
- Conversion of graphite to diamond
- Decomposition of water
- Dehydrogenation of ethane to ethylene
- none of these
Answer : 4
Question 9 : Heat of solution in a system in which both solute and solvent are liquids is termed as
- heat of solvation.
- heat of hydration.
- standard integral heat of solution.
- heat of mixing.
Answer : 4
Question 10 : A solution is made by dissolving 1 kilo mole of solute in 2000 kg of solvent. The molality of the solution is
- 2
- 1
- 0.5
- 0.5
Answer : 3
Question 11 : Average molecular weight of air is about
- 21
- 29
- 23
- 79
Answer : 2
Question 12 : 6 gms of magnesium (atomic weight = 24), reacts with excess of an acid, the amount of H2produced will be __________ gm.
- 0.5
- 1
- 3
- 5
Answer : 1
Question 13 : Pick out the wrong unit conversion of calorific value.
- 1 kcal/kg = 1.8 BTU/lb = 4.186 kJ/kg.
- 1 BTU/ft3 = 8.9 kcal/m3 = 0.038 MJ/m3.
- 1 BTU/lb = 2.3 kcal/kg.
- 1 kcal/m3 = 0.1124 BTU/ft3.
Answer : 1
Question 14 : Increasing the temperature of an aqueous solution will cause decrease in its
- molality
- mole fraction
- weight percent
- molarity
Answer : 4
Question 15 : S.T.P. corresponds to
- 1 atm. absolute pressure & 15.5°C
- 760 mm Hg gauge pressure & 15.5°C
- 760 torr & 0°C.
- 101.325 kPa gauge pressure & 15.5°C
Answer : 1
Question 16 : With rise in pressure, the solubility of gases in solvent, at a fixed temperature
- increases
- decreases
- remains unchanged
- decreases linearly
Answer : 1
Question 17 : Pick out the wrong statement.
- ‘Reduced temperature’ of a substance is the ratio of its existing temperature to its critical temperature, both expressed on celsius scale.
- ‘Reduced pressure’ is the ratio of the existing pressure of a substance to its critical pressure.
- ‘Reduced volume’ is the ratio of the existing molal volume of a substance to its critical molal volume.
- none of these.
Answer : 1
Question 18 : Vapor pressure of water at 100°C is about __________ bar.
- 0.1013
- 1.013
- 10.13
- 101.3
Answer : 2
Question 19 : At room temperature, the product [H+] [OH–] in a solution is 10-14 moles/litre. If, [OH–] = 10-6moles/litre, then the pH of the solution will be
- 6
- 8
- 10
- 12
Answer : 2
Question 20 : Pick out the wrong statement.
- The effect of pressure on heat capacity of gases at pressure above one atmosphere and above the critical temperature is negligible.
- The value of Cp of gases increases with increase in pressure, above atmospheric pressure.
- The value of Cp at critical temperature and pressure reaches infinity.
- all (1), (2), and (3).
Answer : 1
Question 21 : In case of a ternery system involving two liquid components and a solute, the ratio of the concentration of the solute in the two phases at equilibrium is called the distribution co-efficient. The distribution co-efficient depends upon the
- solute concentration
- temperature
- both(1) & (2)
- neither (1) nor (2)
Answer : 1
Question 22 : Solution made by dissolving equimolar amounts of different solutes in the same amount of a given solvent will have the
- same elevation in boiling point.
- different elevation in boiling point.
- elevation in boiling point in the ratio of their molecular weights.
- none of these.
Answer : 1
Question 23 : N2 content in a urea sample was found to be only 42%. What is the actual urea content of the sample ? (molecular weight of urea = 60)
- 80%
- 90%
- 95%
- 98%
Answer : 2
Question 24 : Specific gravity on API scale is given by the relation(where, G = specific gravity at 15.5°C).
- °API = 200(G – 1)
- °API = (141.5/G) – 131.5
- °API = (140/G) – 130
- °API = 145 – (145/G)
Answer : 2
Question 25 : Which of the following is not a colligative property ?
- Osmotic pressure
- Depression of freezing point
- Lowering of vapor pressure
- none of these.
Answer : 4
Question 26 : toms of the same element, but of different masses are called
- isobars
- isotones
- isotopes
- none of these
Answer : 3
Question 27 : If pH value of an acidic solution is decreased from 5 to 2, then the increase in its hydrogen ion concentration is __________ times.
- 10
- 100
- 1000
- 10000
Answer : 3
Question 28 : Kopp’s rule is concerned with the calculation of
- thermal conductivity.
- heat capacity.
- viscosity.
- surface tension.
Answer : 2
Question 29 : Density of carbon dioxide is __________ kg/Nm3.
- 44/22400
- 44/22.4
- 22.4/44
- none of these
Answer : 2
Question 30 : Assuming that CO2 obeys perfect gas law, calculate the density of CO2 (in kg/m3) at 263°C and 2 atm
- 1
- 2
- 3
- 4
Answer : 2
Question 31 : One micron is equal to
- 10-4 mm
- 10-4 cm
- 10-6 m
- both(2)&(3)
Answer : 4
Question 32 : Heat capacity of air can be approximately expressed as, Cp = 26.693 + 7.365 x10-3 T, where, Cp is in J/mole.K and T is in K. The heat given off by 1 mole of air when cooled at atmospheric pressure from 500°C to – 100°C is
- 10.73 kJ
- 16.15 kJ
- 18.11 kJ
- 18.33 kJ
Answer : 3
Question 33 : Gases diffuse faster compared to liquids because of the reason that the liquid molecules
- are held together by stronger inter-molecular forces.
- move faster.
- have no definite shape.
- are heavier
Answer : 1
Question 34 : Equal masses of CH4 and H2 are mixed in an empty container. The partial pressure of hydrogen in this container expressed as the fraction of total pressure is
- 1/9
- 8/9
- 1/2
- 5/9
Answer : 2
Question 35 : Molar heat capacity of water in equilibrium with ice at constant pressure is
- 0
- ∞
- 1
- none of these
Answer : 2
Question 36 : If pH value of a solution is 8, then its pOH value will be
- 6
- 1
- 7
- 10
Answer : 1
Question 37 : The chemical nature of an element is independent of
- its atomic number.
- the number of protons or electrons present in it.
- the number of neutrons present in it.
- none of these.
Answer : 3
Question 38 : The heat change for the reaction, C(s) + 2S(s) → CS2(l), is 104.2 kJ. It represents the heat of
- formation
- solution
- combustion
- fusion
Answer : 1
Question 39 : A sample of well water contains 140 gm/m3 Ca2+ ions and 345 gm/m3 Na+ ions. The hardness of the sample of water, expressed in terms of equivalent CaCO3 in gm/m3 is (assuming atomic masses of Ca :40, Na : 23, C : 12, O : 16)
- 350
- 485
- 140
- 345
Answer : 1
Question 40 : One Newton is equal to __________ dynes.
- 102
- 103
- 104
- 105
Answer : 4
Question 41 : A very dilute solution is prepared by dissolving ‘x1‘ mole of solute in ‘x2‘ mole of a solvent. The mole fraction of solute is approximately equal to
- x1/x2
- x2/x1
- 1 – (x1/x2)
- 1/x2
Answer : 1
Question 42 : An ideal gas can be liquified, because
- its molecular size is very small.
- its critical temperature is more than 0°C.
- forces operative between its molecules are negligible.
- it gets solidified directly without becoming liquid.
Answer : 3
Question 43 : The rate of material __________ is zero in case of a steady state system.
- accumulation
- production
- input
- generation
Answer : 1
Question 44 : A metal oxide is reduced by heating it in a stream of hydrogen. After complete reduction, it is found that 3.15 gm of the oxide has yielded 1.05 gm of the metal. It may be inferred that the
- atomic weight of the metal is 4.
- equivalent weight of the metal is 4.
- atomic weight of the metal is 2.
- equivalent weight of the metal is 8.
Answer : 2
Question 44 : CaCO3 contains __________ percent of Ca by weight.
- 40
- 48
- 96
- 12
Answer : 1
Question 45 : Solutions which distil without change in composition are called
- ideal
- saturated
- supersaturated
- azeotropic
Answer : 4
Question 46 : Gases having same reduced temperatures and reduced pressures
- deviate from ideal gas behaviour to the same degree.
- have nearly the same compressibility factor.
- both (1) and (2).
- neither (1) nor (2).
Answer : 3
Question 47 : Which of the following is not a unit of pressure ?
- Torr
- Newton/m2
- Parsec
- Ata, bar or pascal
Answer : 3