List of top Chemistry Questions

If first ionization enthalpy (\(\Delta H\)) values of Na, Mg and Si are respectively 496, 737, and 786 kJ/mol, the first ionization enthalpy value of Al (in kJ/mol) will be:

Observe the following two statements: I. For an isolated system, \( \Delta U = 0 \); \( q = 0 \) II. For a closed system, \( \Delta U = 0 \); \( q \neq 0 \) The correct answer is

The equilibrium constants for the following two reactions are given below at T(K): \[ 2A(g) \leftrightarrow B(g) + C(g), \quad K = 16 \quad \text{and} \quad 2B(g) \leftrightarrow D(g), \quad K = 25. \] What is the value of the equilibrium constant (K) for the reaction given below at T(K)? \[ \frac{1}{2} A(g) \leftrightarrow B(g) \]

Match the following:

Copper matte is a mixture of:

The correct statements of the following are: A) Aniline forms a stable benzene diazonium chloride at 285K.
B) N - Phenylethanamide is less reactive towards nitration than aniline.
C) p - CH\(_3\)C\(_6\)H\(_4\)COCl is Hinsberg reagent.

At 61 K, one mole of an ideal gas of 1.0 L volume expands isothermally and reversibly to a final volume of 10.0 L. What is the work done in the expansion?

The incorrect rule regarding the determination of significant figures is:

Observe the following f-block elements: Eu (Z = 63); Pu (Z = 94); Cf (Z = 98); Sm (Z = 62); Gd (Z = 64); Cm (Z = 96) How many of the above have half-filled f-orbitals in their ground state?

Phosphodiester linkage that joins nucleotides together is present between which carbons of pentose sugar?

What is 'Z' in the given sequence of reactions?

Arrange the following in the correct order of their boiling points:

Which of the following sets are not correctly matched? \[ \text{Molecule} \quad \text{Hybridization} \] \[

Which one of the following order is correct regarding the covalent character of given molecules?

The number average molecular weight (M\(_n\)) of a polymer is 1500. In this polymer, 800 molecules of molar mass 1000, 100 molecules of molar mass 2000 and x molecules of molar mass 5000 are present. What is the value of x?

The monomer which is present in both Bakelite and Melamine polymers is:

What are Y and Z respectively in the given reaction sequence?

Match the following reactions with their corresponding products:

What is the IUPAC name of the product Y in the given reaction sequence?

Phenatole can be prepared from which of the following reactants?

In the given sequence of reactions: \[ \text{P}_4 + \text{NaOH} + \text{H}_2\text{O} \;\longrightarrow\; \dots \;\longrightarrow\; X \;+\; 2\,\text{NaH}_2\text{PO}_2 \;\longrightarrow\; \dots \] The final product obtained with copper and \(\text{H}_2\text{SO}_4\) is:

Which of the following does not evolve \( O_2 \) when made to react with water?

What is 'C' in the given sequence of reactions?

Which of the following statements are correct?

i) \( CCl_4 \) undergoes hydrolysis easily.
(ii) Diamond has directional covalent bonds.
(iii)Fullerene is the thermodynamically most stable allotrope of carbon.
(iv)Glass is a man-made silicate.

Acrolein (X) is one of the chemicals formed when \( O_3 \) and \( NO_2 \) react with unburnt hydrocarbons present in polluted air. The structure of 'X' is: