AIPMT-MAIN Chemistry Questions

The alkali metals from salt-like hydrides by the direct synthesis at elevated temperature. The thermal stability of these hydrides decreases in which of the following orders?

The ground state energy of hydrogen atom is^{-13}.6 eV. When its electron is in the first excited state, its excitation energy is

If the lattice parameter for a crystalline structure is 3.6 Å, then the atomic radius in fcc crystal is

The value of equilibrium constant of the reaction HI (g) ⇌ ½ H₂ (g) + ½ I₂ (g) is 8.0. The equilibrium constant of the reaction H₂ (g) + I₂ (g) ⇌ 2HI (g) will be

If 'a' stands for the edge length of the cubic systems: simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these systems will be respectively

Kohlrausch's law states that at

Which of the following are not state functions? (I) q + w (II) q (III) w (IV) H-TS

The bromination of acetone that occurs in acid solution is represented by this equation CH₃COCH₃(aq) + Br₂(aq) → CH₃COCH₂Br(aq) + H⁺(aq) + Br⁻(aq) These kinetic data were obtained for given reaction concentrations Initial concentrations, M [CH₃COCH₃] [Br₂] [H⁺] 0.30 0.05 0.05 0.30 0.10 0.05 0.30 0.10 0.10 0.05 0.05 0.20 Initial rate, disappearance of Br₂, M s⁻¹ 5.7 × 10⁻⁵ 5.7 × 10⁻⁵ 1.2 × 10⁻⁴ 3.1 × 10⁻⁴ Based on these data, the rate equation is

What volume of oxygen gas (O₂) measured at 0°C and 1 atm, is needed to burn completely 1 L of propane gas (C₃H₈) measured under the same conditions?

Bond dissociation enthalpy of H₂, Cl₂ and HCl are 434, 242 and 431 kJmol⁻¹ respectively. Enthalpy of formation of HCl is

Which of the following statements is not correct?

Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the H⁺ ion concentration in the mixture?

The values of Kₚ₁ and Kₚ₂ for the reactions X ⇌ Y + Z and A ⇌ 2B are in ratio of 9:1. If degree of dissociation of X and A be equal, then total pressure at equilibrium (1) and (2) are in the ratio

If the concentration of OH⁻ ions in the reaction Fe(OH)₃ (s) ⇌ Fe³⁺ (aq) + 3OH⁻ (aq) is decreased by 1/4 times, then equilibrium concentration of Fe³⁺ will increase by

For the gas phase reaction, PCl₅ (g) ⇌ PCl₃ (g) + Cl₂ (g) which of the following conditions is correct?

The rate constants k₁ and k₂ for two different reactions are 10¹⁶ · e⁻²⁰⁰⁰/ᵀ and 10¹⁵ · e⁻¹⁰⁰⁰/ᵀ respectively. The temperature at which k₁ = k₂ is

Standard free energies of formation (in kJ/mol) at 298 K are^{-237}.2, -394.4 and^{-8}.2 for H₂O (l), CO₂ (g) and pentane (g) respectively. The value of E°cell for the pentane-oxygen fuel cell is

The dissociation equilibrium of a gas AB₂ can be represented as, 2AB₂ (g) ⇌ 2AB (g) + B₂ (g). The degree of dissociation is 'x' and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant Kₚ and total pressure P is

The sequence of ionic mobility in aqueous solution is

Percentage of free space in a body centred cubic unit cell is

The correct order of decreasing second ionisation enthalpy of Ti (22), V (23), Cr (24) and Mn (25) is

How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl?

Which of the following complexes exhibits the highest paramagnetic behaviour?

Volume occupied by one molecule of water (density = 1 g cm⁻³) is

Number of moles of MnO₄⁻ required to oxidize one mole of ferrous oxalate completely in acidic medium will be

On the basis of the following E° values, the strongest oxidizing agent is [Fe(CN)₆]³⁻ → [Fe(CN)₆]⁴⁻ + e⁻; E° = -0.35 V Fe²⁺ → Fe³⁺ + e⁻; E° = -0.77 V

Which one of the following arrangements does not give the correct picture of the trends indicated against it?

In which of the following coordination entities the magnitude of ΔO (CFSE in octahedral field) will be maximum (at. no. Co = 27)?

The angular shape of molecule (O₃) consists of

The correct order of increasing bond angles in the following triatomic species is

Four diatomic species are listed below the different sequences. Which of these presents the correct order of their increasing bond order?

Equimolar solutions of the following were prepared in water separately. Which one of the solutions will record the highest pH?

In the hydrocarbon CH₃—C≡C—CH₂—CH₃, the state of hybridization of carbons 1, 3 and 5 are in the following sequence

Green chemistry means such reactions which

A strong base can abstract an α-hydrogen from

How many stereoisomers does the molecule CH₃CH = CHCH₂CHBrCH₃ have?

The stability of carbanions in the following is in the order of

The relative reactivities of acyl compounds towards nucleophilic substitution are in the order of

Base strength of is in the order of

A (predominantly) is $$\text{H}_3\text{C}-\underset{\substack{| \\ \text{CH}_3}}{\text{CH}}-\text{CH}=\text{CH}_2 + \text{HBr} \rightarrow \text{A}$$

Which one of the following is most reactive towards electrophilic attack?

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be

In a $\text{S}_\text{N}2$ substitution reaction of the type$$\text{R}-\text{Br} + \text{Cl}^- \xrightarrow{\text{DMF}} \text{R}-\text{Cl} + \text{Br}^-$$Which one of the following has the highest relative rate?

Acetophenone when reacted with a base, C₂H₅ONa, yields a stable compound which has the structure?

In a reaction of aniline a coloured product C was obtained. The structure of C would be

Which of the following statements is not true?

A competitive inhibitor of succinic dehydrogenase is

According to Central Pollution Control Board (CPCB), which particulate size in diameter (in micrometers) of the air pollutants is responsible for greatest harm to human health?

Modern detergents contain enzyme preparations of