List of top Questions asked in COMEDK UGET

Benzene diazonium chloride when warmed with water gives a compound, whose sodium salt when reacted with allyl bromide gives compound [X]. Identify [X].

Given that the standard enthalpy of combustion of \(C(s)\) and \(CS_2(l)\) are \(-393.3\) and \(-1108.76 \, \text{kJ/mol}\) respectively and the standard enthalpy of formation of \(CS_2\) is \(128.02 \, \text{kJ/mol}\). What is \(\Delta H_f^\circ\) of \(SO_2\)?

Arrange the following in the decreasing order of their \(pK_a\) values.

Choose the correct statement.

Which one of the following statements is correct?

Match the coordination compounds in Column I having the given type of hybridisation of \(M^{n+}\) ion and magnetic moment as given in Column II.

An unsaturated hydrocarbon [A] undergoes the following series of reactions. Identify [A].

Which one of the following reactions does not give the correct combination of reactants and the major products formed in the reaction?

For a reaction \(X_2(l) + Y_2(g) \rightleftharpoons 2XY(g)\), the \(\Delta H^0\) and \(\Delta S^0\) are \(+29.3 \, \text{kJ/mol}\) and \(104.1 \, \text{J K}^{-1}\text{mol}^{-1}\) respectively at 298 K. Find the free energy change in kJ/mol.

Identify the compound which gives an optically active haloalkane on reaction with \(H_2/Ni\) on heating.

An organic compound [X] reacts with \(H_2/Pd-BaSO_4\) to give compound [Y], which reduces Tollens' reagent and undergoes Cannizzaro's reaction. On rigorous oxidation of [Y] in presence of \(KMnO_4/H^+\), phthalic acid is the product obtained. What is [X]?

A current of 2.5 amperes is passed through 800 ml of 0.48 M solution of CuSO$_4$ for 1.0 hour with a current efficiency of 80%. If the volume of the solution remains unchanged, what is the final molarity of the solution?

If \(X\) is a haloalkane with a single chlorine atom per molecule and the percentage of Cl is 55, what would be the number of Cl atoms present in 0.1 g of the haloalkane? Atomic mass of Cl = 35.5 g/mol

From the given covalent compounds (A to F) identify the pair of molecules which have:
(i) Two lone pairs of electrons on the central atom.
(ii) One lone pair of electrons on the central atom.
A. \(SO_2\)
B. \(ClF_3\)
C. \(BF_3\)
D. \(BrF_5\)
E. \(XeF_4\)
F. \(SF_6\)

A certain orbital having 2 angular nodes and no radial nodes is:

Arrange the following free radicals in the increasing order of their stability:

Both reactions (i) and (ii) give the same compound \(X\) as the major product. Identify \(X\).
\[ \text{(i) } 3\text{-Methylbut-1-ene} + HCl \rightarrow X \] \[ \text{(ii) Neopentyl alcohol} + HCl \ (\text{anh. } ZnCl_2) \rightarrow X \]

Solubility product of the sparingly soluble salt \(AgBrO_3\) in aqueous medium is \(9.3 \times 10^{-10}\). Calculate the mass in gram of \(AgBrO_3\) present in \(100 \, ml\) of its saturated solution. (Molar mass of \(AgBrO_3 = 236 \, g \, mol^{-1}\))

Two chemical reactions of the same order have equal frequency factor value. Their activation energies differ by 26.8 kJ/mol. At 300 K if \(k_2 = xk_1\), find the value of \(x\).

What is the reduction potential of a half-cell consisting of a Pt electrode dipped in \(2.2M\ Fe^{2+}\) and \(0.04M\ Fe^{3+}\) solution where the reaction taking place is conversion of \(Fe^{3+}\) ions to \(Fe^{2+}\)? Given \(E^\circ(Fe^{3+}/Fe^{2+})=0.771\ V\)

Choose the incorrect statement.

Arrange the following compounds in the decreasing order of the molar conductivities of their aqueous solutions.

Identify the correct statement.
p

The concentration and percentage purity of oxalic acid can be determined by titration with \(KMnO_4\) in presence of dil. \(H_2SO_4\). Instead of dil. \(H_2SO_4\), dil. HCl cannot be used because

A non-volatile solute A weighing \(60 \, g\) when dissolved in \(212 \, g\) of the solvent xylene reduces its vapour pressure to \(60\%\). What is the molar mass of A in \(g \, mol^{-1}\)? Given molar mass of xylene \(= 106 \, g \, mol^{-1}\).