List of top Chemistry Questions

The incorrect statement in the following is:

At T(K), $ K_c $ value for $ \text{AO}_2(g) + \text{BO}_2(g) \rightleftharpoons \text{AO}_3(g) + \text{BO}(g) $ is 16. In a closed 1 L flask, one mole each of $ \text{AO}_2 $, $ \text{BO}_2 $, $ \text{AO}_3 $, and $ \text{BO} $ are taken and heated to T(K). What is the concentration (in mol L$^{-1}$) of $ \text{AO}_3 $ at equilibrium?

At 25$^\circ$C, the percentage of ionization of 'x' M acetic acid is 4.242. What is the value of x? $(K_a = 1.8 \times 10^{-5})$

For which of the following processes entropy change ($\Delta S$) is negative?
I) Sublimation of dry ice
II) Freezing of water
III) Crystallisation of the dissolved substance
IV) Burning of rocket fuel

Identify the correct statements from the following:
I) Work is a path function.
II) Enthalpy is an extensive property.
III) Lattice enthalpy of ionic compounds can be obtained from Born–Haber cycle.

1.84 g of a mixture of CaCO$_3$ and MgCO$_3$ is strongly heated to get a residue of 0.96 g. The percentage of CaCO$_3$ in the mixture is

The most probable speed $u_{mp}$ of 8 g of H$_2$ is $2 \times 10^2$ ms$^{-1}$. The kinetic energy (in J) of the same amount of H$_2$ gas is

At T(K), a gaseous mixture contains H$_2$ and O$_2$. The total pressure of the mixture is 2 bar. The partial pressure of H$_2$ is 1.778 bar. What is the weight (w/w) percentage of H$_2$ in the mixture?

How many of the following molecules / ions have a trigonal planar structure?
$ \text{BO}_3^{3-}, \, \text{NH}_3, \, \text{PCl}_3, \, \text{BCl}_3, \, \text{ClF}_3, \, \text{XeO}_3 $

The correct order of atomic radii of C, Al and S is

Which of the following sets of quantum numbers is not possible for the electron?

The wavenumber of the first line ($n_2 = 3$) in the Balmer series of hydrogen is $ \overline{\nu}_1 \, \text{cm}^{-1} $. What is the wavenumber (in cm$^{-1}$) of the second line ($n_2 = 4$) in the Balmer series of He$^{+}$?

Match the following:

List-I (Metal in drinking water)	List-II (Maximum prescribed concentration in ppm)
A) Mn	I) $ 0.05 $
B) Zn	II) $ 3.0 $
C) Cd	III) $ 0.005 $
D) Cu	IV) $ 5.0 $

Consider the following
Assertion (A): Dipole moment of NF$_3$ is lesser than NH$_3$
Reason (R): In NF$_3$, the orbital dipole due to lone pair of electrons is in the opposite direction to the resultant dipole moment of the three N-F bonds.
The correct answer is:

Which of the following represents Gattermann reaction?

The incorrect statement about the product ‘Z’ in the given reaction sequence is

What is the end product 'R' in the reaction sequence?

What is the major product Y in the following reaction sequence?

A halide with formula C₆H₁₃Br gave two isomeric alkenes A and B on dehydrobromination. On ozonolysis of mixture of A and B the following compounds were obtained: CH₃COCH₃, CH₃CHO, CH₃CH₂CHO and (CH₃)₂CHCHO. The halide is:

The correct statement regarding the mechanism involved in the above reactions is

Match the following:

List-I (reaction)	List-II (catalyst)
A) SO₂(g) + Cl₂(g) → SO₂Cl₂(l)	I) Pt / Rh gauge
B) 2SO₂(g) + O₂(g) → 2SO₃(g)	IV) V₂O₅
C) 4HCl + O₂ → 2Cl₂ + 2H₂O	II) CuCl₂
D) 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)	III) Charcoal

Identify the sets in which enzyme, its source and enzyme reaction are correctly matched:
I) maltase, yeast; proteins $\rightarrow$ peptides
II) diastase, malt; starch $\rightarrow$ maltose
III) zymase, yeast; glucose $\rightarrow$ C$_2$H$_5$OH + CO$_2$

Identify the correct statements from the following:
I) In adsorption process, both enthalpy and entropy decrease.
II) In general, physisorption is an irreversible process.
III) The catalyst used in the decomposition of potassium chlorate is manganese dioxide.

A → P is a first order reaction. The reaction was started at 10.00 AM. At 10.10 AM, the concentration of A was x mol L^-1. At 10.20 AM, the concentration of A was y mol L^-1. The half life (in min) of the reaction is equal to:

When 3 amp current was passed through an aqueous solution of salt of a metal M (atomic weight 106.4 u) for 1 hour, 2.977 g of Mⁿ⁺ was deposited at cathode. The value of n is (1 F = 96500 C mol^-1)

List-I (Metal in drinking water)	List-II (Maximum prescribed concentration in ppm)
A) Mn	I) \( 0.05 \)
B) Zn	II) \( 3.0 \)
C) Cd	III) \( 0.005 \)
D) Cu	IV) \( 5.0 \)