List of top Chemistry Questions

Consider the reactions
I. \( CO + 3H_2 \xrightarrow{A} CH_4 + H_2O \)
II. \( CO + 2H_2 \xrightarrow{B} CH_3OH \)
III. \( O_2 + 2H_2 \xrightarrow{C} 2H_2O \) The catalysts A, B, C are respectively
In the above reaction electrophile is substituted at meta position only, due to
electrophile is substituted

I. Electron density is more at ortho & para position
II. Electron density is relatively less at ortho & para position
III. Electron density is less at meta position
IV. Electron density is relatively more at meta position Correct answer is
Among the following the correct statements are
I. LiH, BeH\( _2 \) and MgH\( _2 \) are saline hydrides with significant covalent character
II. Saline hydrides are volatile
III. Electron - precise hydrides are Lewis bases
IV. The formula for chromium hydride is CrH The correct option is
IUPAC name of the following molecule is
4-Bromo-6-chloro-3,7-diethylnon-7-en-1-yn-5-one
Out of seven crystal systems, how many have face-centred unit cells?
Which of the following statements are not correct?
i. Atomic radius of Ga is less than that of Al
ii. The order of ionization enthalpy of group 13 elements is B>Al>Ga>In>Tl
iii. Boron trioxide is amphoteric in nature
White metal is an alloy of
Identify the correct statements from the following.
i. Melting points and boiling points of group 15 elements are much higher than those of corresponding group 14 elements
ii. SiO only exists at high temperatures
iii. PbI\( _4 \) does not exist
iv. Buckminster fullerene contain twelve 6-membered carbon rings and twenty 5 - membered carbon rings.
If the standard enthalpy of sublimation \( (\Delta_{sub}H^\circ) \) of solid \( CO_2 \), naphthalene, Li and Na are 25.2, 73.0, 162, 108 kJ mol\(^{-1} \) respectively, the order of sublimation of these substances with temperature is
The weight percentage of C and H in a hydrocarbon is in the ratio of 4:1. What is its empirical formula?
At a given temperature, the density of an ideal gas is proportional to (P = pressure of ideal gas)
Identify the correct statements from the following
(A) The compressibility factor (Z) for an ideal gas is 1
(B) Uranium isotopes (\( ^{235}U \) and \( ^{238}U \)) are separated by converting them into \( UF_6 \) vapours
(C) Decrease in temperature increases the kinetic energy of gas molecules
Conjugate acid and conjugate base of \( HCO_3^- \) are respectively
One mole of \( PCl_5(g) \) was heated in a 1L closed flask at 500 K. At equilibrium, 0.1 mole of \( Cl_2(g) \) was formed. What is its \( K_p \) (in atm)? (Given R = 0.082 L atm mol\(^{-1} \) K\(^{-1} \))
When 'X' g of graphite is completely burnt in a bomb calorimeter in excess of \( O_2 \) at 298 K and 1 atm pressure as given in the equation $$ \text{C(graphite)} + O_2(g) \rightarrow CO_2(g) $$ The temperature of calorimeter raised from 298 K to 302 K. If the heat capacity of the calorimeter and molar enthalpy change for the reaction at 1 atm and 298 K are 20.7 kJ K\(^{-1} \) and -248.4 kJ mol\(^{-1} \), 'X' in g is
Correct order of basic strength of metallic hydroxides
Which of the following fluorides of Xenon does not exist?
Which of the following oxides is highly basic?
Match the following
List-I (Elements)
A. Alkali metals
B. Alkaline earth metals
C. Halogens
D. Noble gases
List-II (Valence shell Configuration)
I. \( ns^2 np^6 \)
II. \( ns^2 np^5 \)
III. \( ns^2 \)
IV. \( ns^1 \)
Which of the following electronic transitions in hydrogen atom will require the highest energy?
The correct order of bond angles of the following is
I. \( \text{H}_2\text{O} \)
II. \( \text{NH}_3 \)
III. \( \text{CH}_4 \)
IV. \( \text{SO}_2 \)
Given equilibrium constants: H$_2$CO$_3$ ⇌ 2H$^+$ + CO$_3^{2–}$, $K = 2 \times 10^{-17}$
H$_2$CO$_3$ ⇌ H$^+$ + HCO$_3^-$, $K = 4 \times 10^{-7}$
Then the equilibrium constant for: HCO$_3^-$ ⇌ H$^+$ + CO$_3^{2–}$ is

Match the following:

PropertyExpression
A. πI. Kb · m
B. ΔTfII. Kf · m
C. ΔTbIII. CST
D. (P0 - P) / P0IV. (n1 / (n1 + n2))

The correct increasing order for the wavelengths of absorption in the visible region for the following Co$^{3+}$ complexes is:
(i) [Co(NH$_3$)$_6$]$^{3+}$
(ii) [Co(H$_2$O)$_6$]$^{3+}$
(iii) [Co(en)$_3$]$^{3+}$

Given below are two statements
Assertion (A): Ethylamine is stronger base than ammonia
Reason (R): It is due to $-$I effect of ethyl group
The correct answer is