Start learning →

BITSAT Hydrocarbons — practice questions

Explore 27 free Hydrocarbons questions in BITSAT Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

Practise Hydrocarbons with Quill →

Hydrocarbons questions and exercises with answers

Showing questions 1–27 of 27.

Hydrocarbons are organic compounds composed exclusively of:Read the answer and worked solution →In the presence of organic peroxides, addition of HBr to propene gives predominantly:Read the answer and worked solution →Wurtz reaction is used to prepare:Read the answer and worked solution →Match each scientist to their contributionRead the answer and worked solution →Ionic or covalent?Read the answer and worked solution →Complete the driver of bond formationRead the answer and worked solution →Single, double and triple bondsRead the answer and worked solution →True or false: Lewis structuresRead the answer and worked solution →Complete the definition of resonanceRead the answer and worked solution →Tap every bond parameter the chapter namesRead the answer and worked solution →True or false: ionic solidsRead the answer and worked solution →Assertion and reasonRead the answer and worked solution →Two are true, one is notRead the answer and worked solution →Three of these are wrong. Find the one that holds.Read the answer and worked solution →Bonded pair or lone pair?Read the answer and worked solution →Flip and pair: term with meaningRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Order the reasoning: why resonance is neededRead the answer and worked solution →Reading the definitions backRead the answer and worked solution →True or false: what bond parameters affectRead the answer and worked solution →Bond parameters in useRead the answer and worked solution →Which parameter answers this?Read the answer and worked solution →True or false: resonanceRead the answer and worked solution →Order the steps: draw a Lewis structureRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Assertion and reason: structureRead the answer and worked solution →Flip and pair: parameter with what it measuresRead the answer and worked solution →

Worked practice questions

Hydrocarbons are organic compounds composed exclusively of:

  1. Carbon and oxygen
  2. Carbon and hydrogen
  3. Carbon and nitrogen
  4. Hydrogen and nitrogen
Show answer and solution

Correct answer: B. Carbon and hydrogen

By definition, hydrocarbons contain **only** carbon and hydrogen atoms. Adding oxygen, nitrogen, halogens, etc. produces other functional-group families (alcohols, amines, halides). Three main classes: - **Alkanes**: only single C-C bonds, $C_nH_{2n+2}$. - **Alkenes**: contain at least one C=C double bond, $C_nH_{2n}$. - **Alkynes**: contain at least one C≡C triple bond, $C_nH_{2n-2}$. Aromatic hydrocarbons (e.g. benzene) are a special case.

Open this question →

In the presence of organic peroxides, addition of HBr to propene gives predominantly:

  1. 1-bromopropane (anti-Markovnikov)
  2. propan-1-ol
  3. 2-bromopropane (Markovnikov)
  4. propane
Show answer and solution

Correct answer: A. 1-bromopropane (anti-Markovnikov)

Kharasch peroxide effect: HBr in the presence of organic peroxides (e.g. benzoyl peroxide) adds **anti-Markovnikov** via a free-radical mechanism. Br ends up on the **less** substituted carbon. Product: 1-bromopropane. Why: the radical chain involves a Br• radical adding to the alkene first. Br• prefers the less-substituted carbon, forming the more stable carbon radical. Then HBr donates H• to complete the addition. Notably, the peroxide effect is **specific to HBr**. HCl and HI don't show it.

Open this question →

Wurtz reaction is used to prepare:

  1. Alkenes from alkyl halides
  2. Symmetric alkanes from alkyl halides
  3. Alcohols from alkanes
  4. Carboxylic acids from alkanes
Show answer and solution

Correct answer: B. Symmetric alkanes from alkyl halides

**Wurtz reaction**: $2 R X + 2 Na \xrightarrow{\text{dry ether}} R{-}R + 2 NaX$. Two alkyl halide molecules combine, with sodium metal as the reducing agent, to give a higher symmetric alkane with double the carbon chain. Example: $\mathrm{CH_3 I + CH_3 I \xrightarrow{2Na} CH_3 CH_3}$ (ethane). Limitation: doesn't work well for asymmetric alkanes — mixing two different RX gives a statistical mixture of R-R, R'-R' and R-R', hard to separate. So Wurtz is best for symmetric products.

Open this question →

How to practise

  1. Choose a Hydrocarbons question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

More Chemistry topics

Chemical EquilibriumElectrochemistryCoordination CompoundsElectrochemical SeriesIdeal and Non-Ideal SolutionsIdeal SolutionsNon-Ideal SolutionsReactions in Aqueous Solution