List of top Chemistry Questions asked in CUET (UG)

Amines are important class of organic compounds which are basic in nature. They are generally derived by replacing one or more hydrogen atoms of ammonia molecule by alkyl / aryl group(s). In nature, they are generally found in proteins, vitamins, alkaloids and hormones. Two biologically active compounds namely adrenaline and ephedrine contain secondary amino group and are used to increase blood pressure.
Like ammonia, nitrogen atom of amines is trivalent and carries an unshared pair of electrons. Nitrogen orbitals in amines are therefore, sp³ hybridized and the geometry of amine is pyramidal. Due to the presence of unshared pair of electrons, the angle C–N–E (where E is C or H) is less than 109.5°.
Inductive effects, solvation effects, steric effects etc. affect the basic strength of amines. Amines are classified as primary (1°), secondary (2°), and tertiary (3°) depending upon the number of hydrogen atoms replaced by alkyl or aryl groups in ammonia molecule. Amines can be prepared from various compounds like reduction of nitro, nitriles, amides etc. compounds. Amines are engaged in intermolecular hydrogen bonding. Aliphatic and aromatic primary amines show positive carbylamine reaction. A colourless crystalline solid benzene diazonium chloride can be obtained from aniline by reacting with sodium nitrite and hydrochloric acid at 273–278 K.

Concept of Solution
There are several ways by which concentration of solution is quantitatively described: molality, molarity, mole fraction, ppm, mass %. Liquid‑liquid solutions can be classified as ideal and non‑ideal solution on the basis of Raoult's law. Suppose the molecules of two components are represented by A and B respectively. In pure components, the intermolecular attractive interaction will be of types A-A and B-B, whereas in the binary solution, A-B type of interactions will also be present. If intermolecular attractive forces between the A-A and B-B are nearly equal to those between A-B, ideal solution is formed.
The properties of solution which depend on the number of solute particles irrespective of their nature relative to the total number of particles present in the solution are called colligative properties.

Phenol is subjected to the following sequence of reactions: \[ \text{Phenol} \xrightarrow[\text{NaOH}]{\text{CO}_2} A \xrightarrow{\text{H}^+} B \xrightarrow[\text{Zn(Hg)}]{\text{Conc. HCl}} C \xrightarrow[\Delta]{NH_2NH_2/KOH} D \] If \(A\) is formed via Kolbe–Schmitt reaction and the final product \(D\) is obtained after the given sequence, then \(D\) is:

EDTA forms a stable complex with a metal ion \(M^{3+}\). The complex formed is octahedral and represented as \([M(EDTA)]^{-\). Which of the following statements is correct?}

Which of the following statements regarding lanthanoids is correct?

Consider the following statements regarding carbohydrates: Assertion (A): Sucrose is a non-reducing sugar. Reason (R): In sucrose, both the anomeric carbon atoms of glucose and fructose participate in glycosidic bond formation. Choose the correct option.

A compound \(A\) having molecular formula \(C_7H_8O\) gives a violet colour with neutral \(FeCl_3\). On treatment with excess \(CH_3I/K_2CO_3\), it forms compound \(B\). Ozonolysis of \(B\) followed by reductive workup \((Zn/H_2O)\) gives one mole of methanal and one mole of anisaldehyde. The number of phenolic compounds among \(A\), \(B\), and the ozonolysis products is:

The molar conductivity of \(CH_3COOH\) at a certain concentration is \(39.0\ \Omega^{-1}\,cm^2\,mol^{-1}\). Given that the limiting molar conductivities are: \[ \Lambda_m^\circ(HCl)=426.0\ \Omega^{-1}\,cm^2\,mol^{-1} \] \[ \Lambda_m^\circ(CH_3COONa)=91.0\ \Omega^{-1}\,cm^2\,mol^{-1} \] \[ \Lambda_m^\circ(NaCl)=126.0\ \Omega^{-1}\,cm^2\,mol^{-1} \] The degree of dissociation of acetic acid at this concentration is:

Aldehyde \(A\) undergoes Cannizzaro reaction to give compounds \(B\) and \(C\). Compound \(B\) on oxidation gives benzoic acid. Compound \(C\) gives positive iodoform test after suitable oxidation. Compound \(A\) is:

A coordination compound has the formula \[ [Co(NH_3)_4Cl_2]Cl \] The magnetic moment of the complex is found to be approximately \(4.9\ BM\). The hybridization and geometry of the complex ion are respectively:

A first-order reaction has a rate constant of \(2.0\times10^{-3}\ s^{-1}\) at \(300\ K\) and \(8.0\times10^{-3}\ s^{-1}\) at \(330\ K\). Assuming the Arrhenius equation to be valid, the activation energy of the reaction is closest to:

For the cell reaction \[ Zn(s)+Cu^{2+}(aq)\rightarrow Zn^{2+}(aq)+Cu(s) \] the standard cell potential is \(1.10\ V\). If \[ [Zn^{2+}] = 0.10\ M \] and \[ [Cu^{2+}] = 1.0\times10^{-3}\ M \] at \(298\ K\), the cell potential is closest to:

Which of the following statements regarding actinoids is correct?

Which reagent is used to distinguish between ethanal and propanone?

Which reagent converts phenol into salicylaldehyde?

Which of the following complexes is diamagnetic?

For a second-order reaction, the unit of rate constant is:

The major product obtained when benzene diazonium chloride is heated with water is:

An organic compound gives a positive semicarbazide test and on reduction produces propan-2-ol. The compound is:

Cumene is industrially used for the preparation of phenol. During the manufacture of phenol from cumene, which of the following compounds is obtained as a valuable by-product?

The magnetic moment of a transition metal complex is found to be \(4.90\) BM. The number of unpaired electrons present is:

Consider the following reaction sequence: \[ 2CH_3CHO \xrightarrow{\text{Dil. NaOH}} X \] \[ X \xrightarrow{\Delta} Y \] The major product \(Y\) formed in the above reaction is:

Assertion (A): Sucrose is a non-reducing sugar and does not exhibit mutarotation.
Reason (R): In sucrose, both anomeric carbon atoms are involved in glycosidic bond formation.

Phenol is subjected to the following sequence of reactions: \[ \text{Phenol} \xrightarrow{\text{Kolbe-Schmitt}} A \xrightarrow{\text{SOCl}_2} B \xrightarrow{\text{Clemmensen Reduction}} C \xrightarrow{\text{Reimer-Tiemann}} D \] The functional group present in the final product \(D\) is:

The molar conductivities at infinite dilution of \(HCl\), \(CH_3COONa\) and \(CH_3COOH\) are \(426.0\), \(91.0\) and \(390.5\ \Omega^{-1}cm^2mol^{-1}\), respectively. If the molar conductivity of \(0.01\,M\) acetic acid solution is \(15.62\ \Omega^{-1}cm^2mol^{-1}\), the value of \(K_a\) is: