List of top Chemistry Questions

Identify the incorrect statement regarding the interstitial compounds.

$R \to P$ is a first-order reaction. The concentration of R changed from 0.04 to 0.03 mol L$^{-1}$ in 40 minutes. What is the average velocity of the reaction in mol L$^{-1}$ s$^{-1}$?

Which of the following are carbonate ores?
I. Siderite
II. Kaolinite
III. Calamine
IV. Sphalerite

Orthophosphorus acid on disproportionation gives PH$_3$, and another oxoacid of phosphorus X. The basicity of X is

Which of the following statements regarding adsorption theory of heterogeneous catalysis is not correct?

What is 'Z' in the following reaction sequence? (Alcohol = colorless) $$ \mathrm{C_3H_6} \xrightarrow[\text{CCl}_4]{\mathrm{Br_2}} \mathrm{X} \xrightarrow[\Delta]{\text{i) KOH/alcohol} \\ \text{ii) NaNH}_2} \mathrm{Y} \xrightarrow[\mathrm{Hg}^{2+}, \mathrm{H}^+]{333\,K} \mathrm{Z} $$

Which one of the following gases is the major contributor to global warming?

A metal crystallizes in simple cubic lattice. The radius of the metal atom is $x\, pm$. What is the volume of the unit cell in $pm^3$?

Consider the following: Statement I: CCl₄ does not undergo hydrolysis. But SiCl₄ undergoes hydrolysis.
Statement II: Thermal and chemical stability of GeX₄ is more than GeX₂.

At $T(K)$, the vapor pressure of water is $x$ kPa. What is the vapor pressure (in kPa) of 1 molal solution containing non-volatile solute?

Elements X and Y form two non-volatile compounds (XY and XY$_2$). When 10 g of XY is dissolved in 50 g of ethanol, the depression in freezing point ($\Delta T_f$) was 5.333 K. When 10 g of XY$_2$ is dissolved in 50 g of ethanol, the $\Delta T_f$ was 2.2857 K. What are the atomic weights of X and Y respectively?
($K_f = 2 \, \text{kg mol}^{-1}$)

In Solvay process, $\mathrm{NH_3}$ is recovered when the solution containing $\mathrm{NH_4Cl}$ is treated with compound ‘X’. What is ‘X’?

The conjugate base of phosphorus acid is $ x $. The conjugate base of oleum is $ y $. What are $ x $ and $ y $, respectively?

Which of the following reactions give $\mathrm{H_2}$ as one of the products? (Reactions are not balanced.)

• $\mathrm{NaBH_4 + I_2}$
• $\mathrm{B_2H_6 + N(CH_3)_3}$
• $\mathrm{Al + NaOH + H_2O}$
• $\mathrm{BF_3 + NaH}$

At temperature $ T(K) $, the equilibrium constant $ K_c $ for the reaction: $$ \mathrm{AO_2(g) + BO_2(g) \rightleftharpoons AO_3(g) + BO(g)} $$ is 16. In a 1 L flask, one mole each of $\mathrm{AO_2}$, $\mathrm{BO_2}$, $\mathrm{AO_3}$, and $\mathrm{BO}$ are taken and heated to $ T(K) $. Identify the correct statements:

• Total number of moles at equilibrium is 4
• At equilibrium, the ratio of moles of $\mathrm{AO_2}$ and $\mathrm{AO_3}$ is 1:4
• Total number of moles of $\mathrm{AO_2}$ and $\mathrm{BO_2}$ at equilibrium is 0.8

Identify the hydride which is not correctly matched with the example given in brackets.

The signs of $\Delta H^\circ$ and $\Delta S^\circ$ for a reaction to be spontaneous at all temperatures respectively are

Consider the following:
Statement-I: Both internal energy (U) and work (w) are state functions.
Statement-II: During the free expansion of an ideal gas into vacuum, the work done is zero.
The correct answer is

100 mL of aqueous solution of 0.05 M Cu$^{2+}$ is added to 1 L of 0.1 M KI solution. The resultant solution was titrated with 0.1 M Na$_2$S$_2$O$_3$ solution using starch indicator until blue color disappeared. What is the volume (in mL) of Na$_2$S$_2$O$_3$ used?

At T(K), the $v_{\text{rms}$ of CO$_2$ is 412 m/s$^{-1}$. What is its kinetic energy (in kJ mol$^{-1}$) at the same temperature? (CO$_2$ = 44 u)

The correct order of increasing bond lengths of C--H, O--H, C--C, and H--H is

Among the ions Mg$^{2+}$, O$^{2-}$, Al$^{3+}$, F$^{-}$, Na$^{+}$, and N$^{3-}$, the ion with the largest size and the ion with the smallest size are respectively

2.0 g of H$_2$ diffuses through a porous container in 10 minutes. How many grams of O$_2$ will diffuse from the same container in the same time under identical conditions?