AIIMS Chemistry Questions

Correct order of electrophilic substitution reaction is:

Which has least covalent radius.

In the given compound, chlorine is present on the first position, methyl group is present on the second position and nitro group is present on the fourth position as shown below. Therefore, IUPAC name of the compound is:

The complete reaction is shown below. In the above reaction, the reactant undergoes 1,4 Michael addition first then the formed intermediate undergoes reduction in the presence of NaBH₄ to form the desired product.

The complete reaction is shown below.

Which is least soluble

$\text{A} \xrightarrow{\text{Ph}-\text{SO}_2\text{Cl}} \text{B} \xrightarrow{\text{KOH}} \text{C} \xrightarrow{\text{C}_2\text{H}_5\text{I}} \text{D}$'C' is water solubleCorrect structure of A and D are

The stability of carbocation depends upon +M effect, +I effect and +H effect. Carbocation (i) shows eight hyperconjugation structures. Carbocation (ii) shows six hyperconjugation structures. Carbocation (iii) shows nine hyperconjugation structures. Carbocation (iv) shows +M effect. Therefore, the correct stability order is:

(i) Buna-S is made up of monomer units, 1,³⁻butadiene and styrene. (ii) Terylene is made up of monomers units, ethylene glycol and terephtalic acid (iii) Elastomer is made up of monomers unit, chloroprene.

The Sₙ2 reaction is a single step reaction and given by less bulky groups. The ease of carbocation towards Sₙ2 reaction is shown below.

Structure of m-methoxy phenol

The final product formed is shown below: Ph−CH₂−CH≡CH−CH₃ (i) Br₂ → Ph−CH₂−CH−CH−CH₃ | Br (ii) Alc.KOH −2HBr → Ph−CH₂−C≡C−CH₃

Which of the following reacts most slowly with nitric acid.

Assertion: $\text{CH}_3 - \underset{\substack{| \\ \text{CH}_3}}{\overset{\substack{\text{CH}_3 \\ |}}{\text{C}}} - \text{O} - \text{CH}_3$ React with HBr to form $(\text{CH}_3)_3\text{CBr}$ and $\text{CH}_3\text{OH}$ Reason: It follows SN1 mechanism

The complete reaction is shown below. The desired product of the given reaction is α,β–unsaturated carbonyl compound.

In processing of steel which of the following allotropes of carbon is used.

The given free radicals are shown below: (I) CH₃–ĊH–CH₃, (II) (III) ĊH₂–CH(CH₃)₂ (IV) ĊH₂–CH₃ The stability of free radicals is mostly affected by the factors like resonance, hyperconjugation and inductive effect. In compound (II), there is high resonance effect due to which it is highly stable than other three compounds. The effect of hyperconjugation is directly proportional to the number alpha hydrogen. So, compound I has six alpha hydrogen atoms, compound III has one alpha hydrogen atom and compound IV has three alpha hydrogen atoms. Therefore, the order is

When phenol reacts with aniline in the presence of diazonium salt (C₆H₅N₂⁺Cl⁻) and a base (KOH), p-hydroxyazobenzene is formed as a major product.

The reaction of glyceraldehyde with Br₂/H₂O.

Product is:

Assertion: Propene reacts with HI in presence of peroxide give¹⁻iodopropane. Reason: 1° free radical is less stable than 2° free radical

Correct order for reaction with alcoholic KOH

Assertion : d⁵ configuration is more stable than d⁴ Reason : d⁵ has more exchange energy as compared to d⁴ because 10 & 6 exchanges are possible in d⁵ & d⁴ respectively.

The given compound is shown below: The IUPAC name of the given compound is 5–Methoxy–3–Nitro cyclohexene.

The final major product formed is shown below: [Diagram showing reaction sequence with carbocation rearrangement]

Which of the following is incorrect about cyanogen gas? (1) It has bent structure (2) It is psuedohalogen. (3) Its behavior is similar to halides. (4) both carbon are sp hybridised

$\text{H}-\overset{\substack{\text{O} \\ ||}}{\text{C}}-\text{H} + \text{CH}_3-\text{CH}=\text{O} \xrightarrow{\text{Conc. NaOH}}$ Find out the products of reaction

Identify structure of ‘P’ and ‘Q’ Correct order of pKa value is:

The +I effect shown by methyl group increases the basic strength of the following compound.

When¹⁻chloro^{-3}-methoxybenzene reacts with nitric acid and sulphuric acid, it forms²⁻chloro^{-4}-methoxy^{-1}-nitrobenzene. The nitro group gets attached to para-position due to steric hindrance at ortho position. The reaction is shown below.

In case of paper chromatography, there are both stationary and dynamic phases present. So, the statement that it is a stationary phase is incorrect.

Assertion: I₂O₅ is used to detect CO. Reason : In I₂O₅ the oxidation number of I is 5.

Oleum is manufactured by adsorption of sulphur trioxide in concentrated sulphuric acid. The reaction is as follows: H₂SO₄ (l) + SO₃ (g) → H₂S₂O₇ (oleum) The structure of oleum is shown below:

(i) $\text{F}_3\text{C}-\text{COOH}$ , (ii) $\text{CH}_3\text{COOH}$ , (iii) $\text{C}_6\text{H}_5\text{COOH}$ ,(iv) $\text{CH}_3\text{CH}_2\text{COOH}$ Correct order of $\text{pK}_\text{a}$ value is:

The structure of the given compound

For balmer series, n¹ = 2 and n² = 3, 4, 5, 6,.........

Suitable reagent for following conversion

Which of the following complex is optically inactive (1) [RhCl(CO)(PPh₃)(NH₃)] (2) [Fe(C₂O₄)₃]³⁻ (3) [Fe(en)₂Cl₂] (4) [Pd(en)₂Cl₂]

The reaction is

The given compounds are shown below. In compound (a), NO₂ possesses the -M effect at para position due to which it is highly acidic than other three compounds. The compound (b) has intermolecular hydrogen bonding and it is less acidic than (a). In compound (d), there is absence of an electron donating group, due to which it is more acidic than compound (c), which has electron donating methyl group. Therefore, the correct order of acidic nature is a > b > d > c.

The complete reaction is shown below.

Correct increasing order for the wavelength of absorption in the visible region for the complexes of Co³⁺ is: (1) [Co(CN)₆]³⁻, [Co(NH₃)₆]³⁺, [Co(NH₃)₅(H₂O)]³⁺[Co(NH₃)₅Cl]²⁺ (2) [Co(CN)₆]³⁻, [Co(NH₃)₅(H₂O)]³⁺[Co(NH₃)₅Cl]²⁺ [Co(NH₃)₆]³⁺, (3) [Co(NH₃)₅]²⁺, [Co(CN)₆]³⁻, [Co(NH₃)₅(H₂O)]³⁺[Co(NH₃)₅Cl]²⁺ (4) [Co(NH₃)₅Cl]²⁺, [Co(NH₃)₅(H₂O)]³⁺, [Co(NH₃)₄]³⁺, [Co(CN)₆]³⁻

A(g) → 2B(g) + C(g) Initial: P₀ 0 0 P₀ - P 2P P Pₜ = P₀ - P + 2P + P = P₀ + 2P Therefore, P = (Pₜ + P₀) / 2 Apply the expression shown below to calculate rate constant. k = (2.303 / t) log [P₀ / (P₀ - P)] Substitute the value of P in above equation.

Assertion: Two sugar units joined by 1,2-glycosidic bond in sucralose. Reason: It contains 1 C-glucose and 2 C -fructose glycosidic bond

The complete reaction is shown below. From the above reaction, it is clear that the amino group is o-p-directing in nature.

Higher the hydration energy of a compound, higher will be its solubility. Be²⁺ has highest hydration energy, therefore, its solubility is maximum.

The reactant, NH₂−CH₂−CH₂−OH possesses two nucleophilic groups −OH and −NH₂, in which is −NH₂ is stronger. So, −NH₂ react at the region at which stable carbocation gets formed. The complete reaction is shown below.

Assertion: Hydroquinone is more acidic than resorcinol. Reason: OH shows I− effect

The complete reaction is shown below.

C + O₂(g) ⟶ CO₂ ...... (i); ΔH = -393 kJ mol⁻¹ H₂ + 1/2 Ω₂ ⟶ H₂O ...... (ii); ΔH = -287.3 kJ mol⁻¹ 2CO₂ + 3H₂O ⟶ C₂H₅OH + 3O₂ ...... (iii); ΔH = 1366.8 kJ mol⁻¹ Find the standard enthalpy of formation of C₂H₅OH(l)