brodidit for students
Home / Practice / ECAT / Chemistry / Inorganic and organic chemistry
Inorganic and organic chemistry
7 ECAT Chemistry questions with answers and explanations.
-
What is the shape of the SF6 molecule?
- 1 Tetrahedral
- 2 Octahedral
- 3 Trigonal bipyramidal
- 4 Square planar
Show answer
Correct answer: Octahedral
Sulphur has six bond pairs and no lone pairs, which gives an octahedral shape.
-
Which catalyst is used in the Haber process for making ammonia?
- 1 Nickel
- 2 Platinum
- 3 Iron
- 4 Vanadium pentoxide
Show answer
Correct answer: Iron
Finely divided iron is the catalyst in the Haber process. Vanadium pentoxide is used in the Contact process.
-
Which reagent distinguishes an aldehyde from a ketone?
- 1 Bromine water
- 2 Tollens' reagent
- 3 Lime water
- 4 Litmus paper
Show answer
Correct answer: Tollens' reagent
Aldehydes reduce Tollens' reagent to give a silver mirror. Ketones do not.
-
According to Markovnikov's rule, the addition of HBr to propene gives mainly:
- 1 1-bromopropane
- 2 2-bromopropane
- 3 Propane
- 4 1,2-dibromopropane
Show answer
Correct answer: 2-bromopropane
The hydrogen goes to the carbon that already has more hydrogens, so bromine ends up on the middle carbon.
-
Which type of alkyl halide reacts fastest by the SN1 mechanism?
- 1 Methyl
- 2 Primary
- 3 Secondary
- 4 Tertiary
Show answer
Correct answer: Tertiary
A tertiary carbocation is the most stable, so tertiary halides react fastest by SN1.
-
What is the product when ethene reacts with steam in the presence of an acid catalyst?
- 1 Ethanal
- 2 Ethane
- 3 Ethanoic acid
- 4 Ethanol
Show answer
Correct answer: Ethanol
Acid-catalysed hydration of ethene adds water across the double bond to give ethanol.
-
What is the hybridisation of sulphur in SF6?
- 1 sp3
- 2 sp3d
- 3 sp3d2
- 4 sp2
Show answer
Correct answer: sp3d2
Six bond pairs need six hybrid orbitals, which use one s, three p and two d orbitals.