List of top Chemistry Questions

Calculate the enthalpy change for the change \( \text{S}_8(g) \rightarrow \text{S}_g(g) \), given that: \[ H_2S_2(g) \rightarrow 2H(g) + 2S(g), \quad \Delta H = 239.0 \, \text{kcal/mol} \] \[ H_2S(g) \rightarrow 2H(g) + S(g), \quad \Delta H = 175.0 \, \text{kcal/mol} \]

Compound ‘A’ of molecular formula \( C_6H_10O \) on treatment with Lucas reagent at room temperature gives compound ‘B’. When compound ‘B’ is heated with alcoholic KOH, it gives isobutene. Compound ‘A’ and ‘B’ are respectively:

For which of the following systems at equilibrium, at constant temperature, will the doubling of the volume cause a shift to the right?

The reagent(s) which can be used to distinguish acetophenone from benzophenone is (are):

In the extraction of Cu, the metal is formed in the Bessemer converter due to the reaction: \[ \text{Cu}_2S + O_2 \rightarrow 2Cu + SO_2 \] The correct equation is:

The chirality of the compound:

For the process \( H_2O(g) \, (1 \, \text{bar}, 373 \, \text{K}) \rightarrow H_2O(g) \, (1 \, \text{bar}, 373 \, \text{K}) \), the correct set of thermodynamic parameters is:

Which of the following compounds is formed when a mixture of \( K_2Cr_2O_7 \) and NaCl is heated with conc. \( H_2SO_4 \)?

Ionisation energy of \( \text{He}^+ \) is \( 19.6 \times 10^{-18} \, \text{J} \, \text{atom}^{-1} \). The energy of the first stationary state (n = 1) of \( \text{Li}^{2+} \) is:

Stomach acid has a pH of approximately 2. Sour milk has a pH of 6. Stomach acid is

When the following 1.0 mol dm\(^{-3}\) aqueous solutions are arranged in order of increasing pH, which is the correct order?

I. Ammonium chloride
II. Ammonium ethanoate
III. Sodium ethanoate

Argon crystallises in fcc arrangement and the density of solid and liquid Ar is 1.59 g/cm\(^3\) and 1.42 g/cm\(^3\), respectively. The percentage of empty space in liquid Ar is

Beryllium gives a compound X with the following percentage composition: Be = 6.1%, N = 37.8%, Cl = 48%, H = 8.1%. The molecular weight of X is 148 g/mol and that of Be is 9 g/mol. The molecular formula of the compound is:

The bond dissociation energies of X₂ , Y₂ and XY are in the ratio of 1 : 0·5 : 1. ΔH for the formation of XY is – 200 kJ mol^–1 . The bond dissociation energy of X₂ will be

How many $\sigma$ bonds and $\pi$ bonds are present in

For the reaction taking place at certain temperature ${NH_2 COONH_4 (s) <=> 2NH_3 (g) + CO_2 (g) }$, if equilibrium pressure is 3X bar then $ \Delta_G$ would be

Beryllium shows diagonal relationship with aluminium. Which of the following similarity is incorrect ?