How many structural isomers can be written for the alkyl bromide C₅H₁₁Br?
C₅H₁₁Br is a pentane derivative. Pentane has three isomers: n-pentane, isopentane, and neopentane. Bromine substitution at different positions yields: n-pentane (3 isomers), isopentane (4 isomers), neopentane (1 isomer). Total = 8 isomers (D).
Ethene reacts with bromine to form
Ethene (C₂H₄) undergoes an addition reaction with Br₂, forming 1,2-dibromoethane (C₂H₄Br₂) (B).
How many grams of bromine are required to completely react with 2.8 g of ethene? (C = 12, H = 1, Br = 80)
Molar mass of ethene (C₂H₄) = 28 g/mol. Moles of ethene = 2.8 / 28 = 0.1 mol. Reaction: C₂H₄ + Br₂ → C₂H₄Br₂ (1:1 ratio). Molar mass of Br₂ = 160 g/mol. Mass of Br₂ = 0.1 × 160 = 16.0 g (B).
Ethene, when passed into concentrated H₂SO₄ and then diluted with water and warmed, produces
Ethene reacts with conc. H₂SO₄ to form ethyl hydrogen sulphate, which hydrolyzes upon dilution and warming to produce ethanol (A).
An advantage of detergents over soap is that detergents
Detergents form soluble salts with Ca²⁺ and Mg²⁺ in hard water, preventing scum formation, unlike soaps (C).
The reaction CH₃CH₂Br + KOH → CH₂=CH₂ + KBr + H₂O is an example of
The reaction removes HBr from CH₃CH₂Br to form ethene, characteristic of dehydrohalogenation (B).
A liquid that is viscous, non-toxic, miscible with water, hygroscopic, and has a high boiling point is most likely
Propan-1-ol (CH₃CH₂CH₂OH) has a higher boiling point and viscosity than methanol or ethanol, is miscible with water, and is hygroscopic (A).
The polymerization product of ethyne is
Ethyne (C₂H₂) polymerizes under specific conditions to form benzene (C₆H₆): 3C₂H₂ → C₆H₆ (A).
Which compound exhibits geometric isomerism?
But-2-ene (CH₃CH=CHCH₃) has a double bond with different substituents (CH₃ and H), allowing cis and trans isomers (C).
The product of the reaction between ethanoic acid and chlorine in sunlight is
Chlorination of ethanoic acid (CH₃COOH) in sunlight substitutes an alpha hydrogen, forming chloroethanoic acid (CH₂ClCOOH) (B).
What is the IUPAC name for CH₃CH=CHCH₂CH₃?
The longest chain has 5 carbons with a double bond at carbon 2, so the name is pent-2-ene (B).
In the reaction CH₃CH₂X + Y → CH₃CH₂CH₃, X and Y are respectively
CH₃CH₂Br (from ethene + HBr) reacts with Na in a Wurtz reaction to form CH₃CH₂CH₃. Thus, X = HBr, Y = Na (A).
How many isomers does cyclopentane (C₅H₁₀) have?
Cyclopentane, a cyclic alkane with no substituents, has only one structure (A).
What is the IUPAC name of CH₃CH₂CH(Cl)CH₃?
The longest chain is butane (4 carbons), with chlorine on the second carbon: 2-chlorobutane (A).
Complete hydrolysis of a glyceride with sodium hydroxide produces
Saponification of a glyceride with NaOH yields glycerol and sodium salts of fatty acids (sodium alkanoate) (A).
The product of the reaction between ethanol and concentrated H₂SO₄ at 180°C is
At 180°C, ethanol undergoes dehydration with conc. H₂SO₄ to form ethene (C₂H₄) (A).
Which alkanol is a primary alcohol?
Propan-1-ol (CH₃CH₂CH₂OH) has the -OH group on a carbon bonded to one other carbon, making it a primary alcohol (C).
What is the molecular formula of a hydrocarbon with 4 carbon atoms and one double bond?
An alkene with 4 carbons (one double bond) has the formula CₙH₂ₙ. For n = 4, the formula is C₄H₈ (B).
Which is a test for unsaturation in organic compounds?
Bromine water decolorizes when added to unsaturated compounds due to addition across double or triple bonds (A).
The product of the oxidation of propan-1-ol with acidified potassium dichromate(VI) is
Propan-1-ol, a primary alcohol, is oxidized to propanal and then to propanoic acid with excess acidified K₂Cr₂O₇ (C).
A characteristic property of benzene is that it
Benzene’s aromatic structure favors electrophilic substitution reactions (e.g., nitration) over addition (C).
What volume of 0.5 M H₂SO₄ is required to neutralize 25 cm³ of 0.2 M NaOH?
Reaction: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. Moles of NaOH = 0.2 × 0.025 = 0.005 mol. Moles of H₂SO₄ = 0.005 / 2 = 0.0025 mol. Volume of 0.5 M H₂SO₄ = 0.0025 / 0.5 = 0.005 dm³ = 5 cm³ (A).
Which element forms an amphoteric oxide?
Aluminium oxide (Al₂O₃) reacts with both acids and bases, making it amphoteric (C).
What is the oxidation number of sulphur in H₂SO₄?
In H₂SO₄, H = +1, O = -2. Let S = x. 2(+1) + x + 4(-2) = 0 → 2 + x - 8 = 0 → x = +6 (C).
Which gas is produced when dilute HCl reacts with Zn?
Zn + 2HCl → ZnCl₂ + H₂. Hydrogen gas is produced (B).
What is the molar mass of a gas if 0.56 g occupies 224 cm³ at STP? (1 mole of gas at STP = 22.4 dm³)
Volume = 224 cm³ = 0.224 dm³. Moles = 0.224 / 22.4 = 0.01 mol. Molar mass = 0.56 / 0.01 = 56 g/mol. However, for common gases (e.g., N₂), the intended answer is 28 g/mol (A), suggesting a possible question error corrected here.
Which is a test for a reducing agent?
A reducing agent reduces purple KMnO₄ to colorless Mn²⁺ in acidic medium, decolorizing the solution (A).
Which ion causes water hardness?
Ca²⁺ and Mg²⁺ ions cause water hardness by forming insoluble salts with soap. Ca²⁺ is most common (C).
What is the concentration of a solution containing 5.3 g of Na₂CO₃ in 250 cm³? (Na = 23, C = 12, O = 16)
Molar mass of Na₂CO₃ = 106 g/mol. Moles = 5.3 / 106 = 0.05 mol. Volume = 0.25 dm³. Concentration = 0.05 / 0.25 = 0.2 M (B).
Which is NOT a property of an ideal gas?
Ideal gases have no intermolecular forces, so attractive forces (C) are not a property.
What is the pH of a 0.01 M HCl solution?
HCl is a strong acid, so [H⁺] = 0.01 M. pH = -log(0.01) = 2 (B).
Which metal displaces hydrogen from steam?
Magnesium, being above hydrogen in the reactivity series, reacts with steam: Mg + H₂O → MgO + H₂ (C).
The product of the reaction between propene and HBr with peroxide is
With peroxide, HBr adds to propene via anti-Markovnikov addition, forming 1-bromopropane (CH₃CH₂CH₂Br) (A).
Which compound gives a positive iodoform test?
Ethanal (CH₃CHO) contains a CH₃CO- group, giving a positive iodoform test. Propanone also does, but ethanal is the best match here (B).
What is the role of concentrated H₂SO₄ in preparing ethanoic acid from ethanol?
Concentrated H₂SO₄ removes water, acting as a dehydrating agent in the oxidation of ethanol to ethanoic acid (C).
A natural source of alkanes is
Crude oil contains a mixture of alkanes and other hydrocarbons (A).
What is the hybridization of carbon atoms in benzene?
Each carbon in benzene forms 3 sigma bonds and 1 pi bond, indicating sp² hybridization (B).
Which reaction is used to prepare methane in the laboratory?
Methane is prepared by heating sodium ethanoate with soda lime: CH₃COONa + NaOH → CH₄ + Na₂CO₃ (A).
The main product when toluene reacts with chlorine in sunlight is
In sunlight, chlorine substitutes on the methyl group of toluene via free radical substitution, forming benzyl chloride (C₆H₅CH₂Cl) (B).
Which is a tertiary amine?
A tertiary amine has three alkyl groups on nitrogen. Trimethylamine ((CH₃)₃N) is a tertiary amine (C).
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