Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. 6
- B. 8
- C. 10
- D. 12
Explanation: Using the ionic product, [H+][OH-]=10^-14, gives [H+]=10^-14/10^-6=10^-8 mol/L. Therefore pH=-log(10^-8)=8.
Correct answer: 8- A. The number of neutrons present in it
- B. The number of protons or electrons present in it
- C. Its atomic number
- D. None of these
Explanation: An element’s chemical identity is fixed by its atomic number, which is the number of protons and, in a neutral atom, electrons.
Correct answer: The number of neutrons present in it- A. 6
- B. 1
- C. 7
- D. 10
Explanation: At 25°C, pH plus pOH equals 14, so pOH = 14 - 8 = 6. This relation follows from the ionic product of water, [H⁺][OH⁻] = 10⁻¹⁴.
Correct answer: 6- A. 21
- B. 29
- C. 23
- D. 79
Explanation: Dry air is mainly nitrogen, with oxygen and small amounts of other gases; its composition gives a weighted average molecular weight of…
Correct answer: 29- A. 2/3
- B. 1/2
- C. 1/3
- D. 1/3 × (298/273)
Explanation: For equal masses, methane produces twice as many moles as oxygen because its molecular weight is 16 compared with oxygen’s 32.
Correct answer: 1/3- A. x1/x2
- B. x2/x1
- C. 1 - (x1/x2)
- D. 1/x2
Explanation: The exact mole fraction is x1/(x1 + x2). Since the solution is very dilute, x1 is negligible compared with x2, giving approximately x1/x2.
Correct answer: x1/x2- A. Weight
- B. Number
- C. Volume
- D. Radius
Explanation: Atomic number is the number of protons in an atom and is therefore a whole-number count.
Correct answer: Number- A. Isobars
- B. Isotones
- C. Isotopes
- D. None of these
Explanation: Isotopes have the same atomic number, meaning the same element, but different numbers of neutrons and therefore different mass numbers.
Correct answer: Isotopes- A. 10 - 50 Angstrom
- B. 50 - 200 microns
- C. 500 - 1000 microns
- D. 5 - 200 milli-microns
Explanation: Colloidal particles typically span roughly 1 to 1000 nanometres, with many textbook definitions giving about 5 to 200 millimicrons.
Correct answer: 5 - 200 milli-microns- A. 5
- B. 10
- C. 15
- D. 20
Explanation: The reaction produces 26 kg of acetylene from 64 kg of calcium carbide, so 1 kg gives about 0.406 kg, or roughly 353 L at NTP.
Correct answer: 10- A. 0.5
- B. 1
- C. 3
- D. 5
Explanation: Six grams of magnesium represents 6/24 = 0.25 mol, and the reaction produces one mole of H2 per mole of Mg.
Correct answer: 0.5- A. 10
- B. 1
- C. 0.1
- D. 1000
Explanation: The pascal is defined as one newton acting over one square metre. Therefore 1 Pa = 1 N/m2.
Correct answer: 1- A. Inventory changes do not take place
- B. Flow rates & composition both are time dependent
- C. Ratio of streams entering/leaving are independent of time
- D. None of these
Explanation: An unsteady-state process has process variables that change with time, such as flow rates or stream compositions.
Correct answer: Flow rates & composition both are time dependent- A. 760 torr & 15°C
- B. 760 mm Hg gauge pressure & 0°C
- C. 1 atm absolute pressure & 0°C
- D. 101.325 KPa gauge pressure & 0°C
Explanation: NTP conventionally means a temperature of 0°C and an absolute pressure of 1 atm, equal to about 101.325 kPa absolute.
Correct answer: 1 atm absolute pressure & 0°C- A. 1015
- B. 10-12
- C. 1012
- D. 109
Explanation: The SI prefix giga denotes one billion, or 10^9. The prefixes micro, tera and peta represent 10^-6, 10^12 and 10^15 respectively.
Correct answer: 109- A. Basic
- B. More acidic
- C. Neutral
- D. Of the same acidity
Explanation: Reducing hydrogen-ion concentration by 100 increases pH by 2 units, from 5.9 to 7.9. Since the final pH is above 7, the solution is basic.
Correct answer: Basic- A. 6.02 x 10^23 atoms of hydrogen
- B. 3.01 x 10^23 molecules of methane
- C. 4 gm atoms of hydrogen
- D. 3 gms of carbon
Explanation: One gram mole of methane is one mole of CH4, containing four gram-atoms of hydrogen because each molecule has four hydrogen atoms.
Correct answer: 4 gm atoms of hydrogen- A. 10
- B. 100
- C. 1000
- D. 10000
Explanation: Hydrogen-ion concentration is 10^-pH, so changing pH from 5 to 2 changes it from 10^-5 to 10^-2. The ratio is 10^3, or 1000 times.
Correct answer: 1000- A. J/kg.°K
- B. 0°K
- C. W/m2.°C
- D. W/m.°K
Explanation: Specific heat capacity at constant pressure is energy required per unit mass per degree of temperature change, so its SI unit is J/(kg·K).
Correct answer: J/kg.°K- A. Molality
- B. Mole fraction
- C. Molarity
- D. Weight percent
Explanation: Molarity is moles of solute per unit volume of solution, and heating usually expands the solution, reducing this ratio.
Correct answer: Molarity