Join WhatsApp ChannelDaily MCQs & Exam Updates

PPSC MCQs

Punjab Public Service Commission — Complete MCQ Bank

1,262 Questions
Exam Preparation Guide

How to prepare for PPSC

PPSC examinations recruit candidates for Punjab government departments and commonly test general knowledge, current affairs, English and post-related subjects.

Punjab AffairsGeneral KnowledgeCurrent AffairsEnglish
Give special attention to Punjab geography, history and administration alongside the advertised post’s specialist syllabus.
Start PracticingTake a Mock Test
PPSC preparation illustration
All Subjects Biology Chemistry Computer Science Current Affairs English Everyday Science General Knowledge Islamic Studies Mathematics Pakistan Studies Physics
241
Chemistry Medium

Which type of reaction in organic chemistry involves replacing a hydrogen atom with another atom or group?

  • AElimination
  • BSubstitution
  • CAddition
  • DHydrolysis
Permalink
Correct Answer: Option B — Substitution
Explanation: Substitution reactions replace one atom or group in a molecule with another as seen when chlorine substitutes hydrogen in methane under UV light producing chloromethane.
Submitted by: PaperMCQs
242
Chemistry Medium

What is the formula for calculating moles from mass and molar mass?

  • AMoles equals mass times molar mass
  • BMoles equals molar mass divided by mass
  • CMoles equals mass divided by molar mass
  • DMoles equals mass times volume
Permalink
Correct Answer: Option C — Moles equals mass divided by molar mass
Explanation: Moles are calculated by dividing the mass of a substance in grams by its molar mass in grams per mole providing the fundamental calculation in all stoichiometry problems.
Submitted by: PaperMCQs
243
Chemistry Medium

Which process is used to separate crude oil into useful fractions based on different boiling points?

  • AFractional distillation
  • BChromatography
  • CCrystallisation
  • DFiltration
Permalink
Correct Answer: Option A — Fractional distillation
Explanation: Fractional distillation separates crude oil into fractions with different boiling points in a fractionating column producing petrol kerosene diesel lubricating oil and bitumen.
Submitted by: PaperMCQs
244
Chemistry Medium

Which element is liquid at room temperature and is the only non-metal element in this state?

  • AMercury
  • BBromine
  • CGallium
  • DCaesium
Permalink
Correct Answer: Option B — Bromine
Explanation: Bromine is the only non-metal element that exists as a liquid at room temperature appearing as a reddish-brown volatile liquid with a pungent irritating smell.
Submitted by: PaperMCQs
245
Chemistry Hard

What is the term for the energy required to remove one electron from a gaseous atom?

  • AElectron affinity
  • BElectronegativity
  • CLattice energy
  • DIonisation energy
Permalink
Correct Answer: Option D — Ionisation energy
Explanation: Ionisation energy is the minimum energy required to remove one electron from a gaseous atom in its ground state with first ionisation energy increasing across a period and decreasing down a group.
Submitted by: PaperMCQs
246
Chemistry Medium

Which type of organic reaction involves the addition of bromine water across a carbon to carbon double bond?

  • AAddition
  • BSubstitution
  • CElimination
  • DHydrolysis
Permalink
Correct Answer: Option A — Addition
Explanation: Addition reactions involve adding molecules across the carbon to carbon double bond of an alkene such as the decolourisation of bromine water used as a test for unsaturation.
Submitted by: PaperMCQs
247
Chemistry Medium

What is formed when an alcohol reacts with a carboxylic acid?

  • AEster and water
  • BSalt and water
  • CSoap
  • DAlkene and water
Permalink
Correct Answer: Option A — Ester and water
Explanation: When an alcohol reacts with a carboxylic acid an esterification reaction occurs producing an ester and water and this reaction requires an acid catalyst such as concentrated sulfuric acid.
Submitted by: PaperMCQs
248
Chemistry Medium

Which organic functional group is present in carboxylic acids?

  • AHydroxyl group
  • BCarboxyl group COOH
  • CCarbonyl group
  • DAmino group
Permalink
Correct Answer: Option B — Carboxyl group COOH
Explanation: The carboxyl group COOH is the functional group present in all carboxylic acids and is responsible for their acidic properties as it can donate a proton to a base.
Submitted by: PaperMCQs
249
Chemistry Medium

Which organic functional group is present in alcohols?

  • ACarbonyl group
  • BHydroxyl group
  • CCarboxyl group
  • DAmino group
Permalink
Correct Answer: Option B — Hydroxyl group
Explanation: The hydroxyl group OH is the functional group present in all alcohols and is responsible for their characteristic properties such as being able to form hydrogen bonds with water.
Submitted by: PaperMCQs
250
Chemistry Medium

What is the chemical formula for calcium hydroxide also known as slaked lime?

  • ACaO
  • BCaCO3
  • CCa(OH)2
  • DCaCl2
Permalink
Correct Answer: Option C — Ca(OH)2
Explanation: Calcium hydroxide Ca(OH)2 also called slaked lime is made by adding water to quicklime CaO and is used in construction water treatment and to neutralise acidic soils.
Submitted by: PaperMCQs
Other Exams
CSS MCQs PMS MCQs FPSC MCQs PPSC MCQs NTS MCQs
Mock Tests
Quick Test (20 Q) Full Mock (60 Q)