List of top Chemistry Questions

500 mL of 0.1M HCl is mixed with 500 mL of 0.02M HA (weak acid) solution. To this solution, 2 g of solid NaOH is added. What is the pH of the resultant solution? (Given} \( K_a \) of HA is \( 4 \times 10^{-10} \), molar mass of NaOH is 40 g/mol, log 2 = 0.3, log 4 = 0.6\bf{)

Which of the following represents the roasting of the ore?

What are X and Y respectively in the following reaction? $$ CH_3CH_2CHO + 2Cu^{2+} + 5OH^- \rightarrow X + Y + 3H_2O $$

Given below are two statements Assertion (A): The enthalpy of formation of graphite is taken as zero. Reason (R): Graphite is thermodynamically most stable allotrope of carbon. The correct answer is

How many of the following are neutral oxides?
CO, NO, Na\(_2\)O, N\(_2\)O, Cl\(_2\)O\(_7\), Al\(_2\)O\(_3\), As\(_2\)O\(_3\)

Observe the following half cell reactions and choose the correct options
(I) 2H2O(l) → O2(g)+4H+ +4e− E0 = 1.23V
(II) H+(aq) + e− → 1/2 H2(g) E0 = 0.00V
(III) 2SO4^2− (aq) → S2O8^2− (aq)+2e− E0 = −1.96V
(a) In dilute H2SO4 solution, H+ ions are reduced at cathode.
(b) In concentrated H2SO4 solution, water is oxidized at anode.
(c) In dilute H2SO4 solution, water is oxidized at anode.
(d) In dilute H2SO4 solution, SO4^2− ions are oxidized at anode.

The O-H bond length in \( H_2O \) in gas phase is

The time required (in hours) to reduce 3 mol of \( Fe^{3+} \) ions to \( Fe^{2+} \) ions with 2.0 amperes of current is (1 F = 96500 C mol\(^{-1} \))

Which of the following ions has [Xe] 4f$^7$ 6s$^0$ as outer electronic configuration?

The vapors of 1 g of an element occupy 2.5625 L exerting a pressure of 0.5 atm at 1000 K. What is the molar mass (in $\text{g mol}^{-1}$) of the element? (Assume vapors follow ideal gas equation. Given $R = 0.082 \text{ L atm mol}^{-1} \text{K}^{-1}$)

Which of the following is not the property of covalent substances?

Among the following organic halides in the increasing order of their dehydrohalogenation reactions in the presence of alcoholic KOH

The correct equation for $K_c$ for the following reaction is:
A(l) + B(g) ⇌ C(g)

The correct order of reactivity of the following towards nucleophilic addition reactions is: \[ \text{I. CH}_3\text{COCH}_3,\quad \text{II. CH}_3\text{CH}_2\text{CHO},\quad \text{III. ClCH}_2\text{CHO} \]

In the given reactions, 'X' and 'Y' respectively are: \[ \ce{C6H5CH2NH2 ⇔[X] C6H5CONH2 ⇒[Y] C6H5NH2} \]

Consider a gas phase reaction which occurs in a closed vessel. \[ 2A (g) \rightarrow 4B (c) + C (g) \] The concentration of B is found to be increased by \( 5 \times 10^{-3} \) mol L\(^{-1}\) in 10 seconds. The rate of disappearance of A (in mol L\(^{-1}\) s\(^{-1}\)) is