List of top Chemistry Questions

Given below are two statements:
Statement I: $\mathrm{K>Mg>Al>B}$ is the correct order in terms of metallic character.
Statement II: Atomic radius is always greater than the ionic radius for any element.
In the light of the above statements, choose the correct answer from the options given below:

A student is given one compound among the following compounds that gives positive test with Tollen's reagent. The compound is:

Consider a mixture $X$ which is made by dissolving $0.4$ mol of $[\mathrm{Co(NH_3)_5SO_4}]Br$ and $0.4$ mol of $[\mathrm{Co(NH_3)_5Br}]SO_4$ in water to make $4$ L of solution. When $2$ L of mixture $X$ is allowed to react with excess $\mathrm{AgNO_3}$, it forms precipitate $Y$. The rest $2$ L of mixture $X$ reacts with excess $\mathrm{BaCl_2}$ to form precipitate $Z$. Which of the following statements is CORRECT?
A solution is prepared by dissolving 0.3 g of a non-volatile non-electrolyte solute A of molar mass 60 g mol$^{-1}$ and 0.9 g of a non-volatile non-electrolyte solute B of molar mass 180 g mol$^{-1}$ in 100 mL H$_2$O at 27$^\circ$C. Osmotic pressure of the solution will be
[Given: R = 0.082 L atm K$^{-1}$ mol$^{-1}$]
Given below are two statements:
Statement I: The number of paramagnetic species among $[\mathrm{CoF_6}]^{3-}$, $[\mathrm{TiF_6}]^{3-}$, $\mathrm{V_2O_5}$ and $[\mathrm{Fe(CN)_6}]^{3-}$ is 3.
Statement II: $ \mathrm{K_4[Fe(CN)_6]}<\mathrm{K_3[Fe(CN)_6]}<\mathrm{[Fe(H_2O)_6]SO_4 \cdot H_2O}<\mathrm{[Fe(H_2O)_6]Cl_3} $ is the correct order in terms of number of unpaired electrons.
Choose the correct answer from the options given below:
Among the following, the CORRECT combinations are
A. \( \mathrm{IF_3} \rightarrow \) T-shaped (\( sp^3d \))
B. \( \mathrm{IF_5} \rightarrow \) Square pyramidal (\( sp^3d^2 \))
C. \( \mathrm{IF_7} \rightarrow \) Pentagonal bipyramidal (\( sp^3d^3 \))
D. \( \mathrm{ClO_4^-} \rightarrow \) Square planar (\( sp^2d \))
Choose the correct answer from the options given below:
The hydrogen spectrum consists of several spectral lines in Lyman series (L$_1$, L$_2$, L$_3$ ...; L$_1$ has lowest energy among Lyman series). Similarly, it consists of several spectral lines in Balmer series (B$_1$, B$_2$, B$_3$ ...; B$_1$ has lowest energy among Balmer lines). The energy of L$_1$ is $x$ times the energy of B$_1$. The value of $x$ is ___ $\times 10^{-1}$. (Nearest integer)
X and Y are the number of electrons involved, respectively during the oxidation of I$^-$ to I$_2$ and S$^{2-}$ to S by acidified K$_2$Cr$_2$O$_7$. The value of X + Y is ___.
Consider two Group IV metal ions X$^{2+}$ and Y$^{2+}$. A solution containing 0.01 M X$^{2+}$ and 0.01 M Y$^{2+}$ is saturated with H$_2$S. The pH at which the metal sulphide YS will form as a precipitate is ___. (Nearest integer)
Given:
$K_{sp}(\mathrm{XS}) = 1 \times 10^{-22}$ at 25$^\circ$C
$K_{sp}(\mathrm{YS}) = 4 \times 10^{-16}$ at 25$^\circ$C
$[\mathrm{H_2S}] = 0.1$ M
$K_{a1} \times K_{a2} (\mathrm{H_2S}) = 1.0 \times 10^{-21}$
$\log 2 = 0.30,\ \log 3 = 0.48,\ \log 5 = 0.70$
In Dumas method for estimation of nitrogen, 0.50 g of an organic compound gave 70 mL of nitrogen collected at 300 K and 715 mm pressure. The percentage of nitrogen in the organic compound is ____ %. (Aqueous tension at 300 K is 15 mm)

Electricity is passed through an acidic solution of Cu$^{2+}$ till all the Cu$^{2+}$ was exhausted, leading to the deposition of 300 mg of Cu metal. However, a current of 600 mA was continued to pass through the same solution for another 28 minutes by keeping the total volume of the solution fixed at 200 mL. The total volume of oxygen evolved at STP during the entire process is ___ mL. (Nearest integer)
Given:
$\mathrm{Cu^{2+} + 2e^- \rightarrow Cu(s)}$ 
$\mathrm{O_2 + 4H^+ + 4e^- \rightarrow 2H_2O}$ 
Faraday constant = 96500 C mol$^{-1}$ 
Molar volume at STP = 22.4 L 
 

200 cc of $x \times 10^{-3}$ M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr's salt solution in acidic medium. Here x = ______ .

Total number of unpaired electrons present in the central metal atoms/ions of \([Ni(CO)_4]\), \([NiCl_4]^{2-}\), \([PtCl_2(NH_3)_2]\), \([Ni(CN)_4]^{2-}\) and \([Pt(CN)_4]^{2-}\) is

Identify the CORRECT set of details from the following: 
A. \([\text{Co}(\text{NH}_3)_6]^{3+}\): Inner orbital complex; \(d^2sp^3\) hybridized 
B. $[\text{MnCl}_6]^{3-}$: Outer orbital complex; $sp^3d^2$ hybridized 
C. $[\text{CoF}_6]^{3-}$: Outer orbital complex; $d^2sp^3$ hybridized 
D. $[\text{FeF}_6]^{3-}$: Outer orbital complex; $sp^3d^2$ hybridized 
E. $[\text{Ni}(\text{CN})_4]^{2-}$: Inner orbital complex; $sp^3$ hybridized}

Iodoform test can differentiate between

A. Methanol and Ethanol
B. CH\(_3\)COOH and CH\(_3\)CH\(_2\)COOH
C. Cyclohexene and cyclohexanone
D. Diethyl ether and pentan-3-one
E. Anisole and acetone

Choose the correct answer from the options given below:

Identify the INCORRECT statements from the following:

A. Notation \( {}^{24}_{12}\mathrm{Mg} \) represents 24 protons and 12 neutrons.
B. Wavelength of a radiation of frequency \( 4.5 \times 10^{15}\ \text{s}^{-1} \) is \( 6.7 \times 10^{-8}\ \text{m} \).
C. One radiation has wavelength \( \lambda_1 \) (900 nm) and energy \( E_1 \). Other radiation has wavelength \( \lambda_2 \) (300 nm) and energy \( E_2 \). \( E_1 : E_2 = 3 : 1 \).
D. Number of photons of light of wavelength 2000 pm that provides 1 J of energy is \( 1.006 \times 10^{16} \).

Choose the correct answer from the options given below: 

[Ni(PPh$_3$)$_2$Cl$_2$] is a paramagnetic complex. Identify the {INCORRECT statements about this complex. A. The complex exhibits geometrical isomerism.
B. The complex is white in colour.
C. The calculated spin-only magnetic moment of the complex is $2.84$ BM.
D. The calculated CFSE (Crystal Field Stabilization Energy) of Ni in this complex is $-0.8\Delta_o$.
E. The geometrical arrangement of ligands in this complex is similar to that in Ni(CO)$_4$.
Choose the correct answer from the options given below:
Consider the following sequence of reactions. The number of bromine atom(s) in the final product (P) will be :
Given below are two statements :
Statement I : Compound (X), shown below, dissolves in \( NaHCO_3 \) solution and has two chiral carbon atoms.

Statement II : Compound (Y), shown below, has two carbons with \( sp^3 \) hybridization, one carbon with \( sp^2 \) and one carbon with \( sp \) hybridization.


In the light of the above statements, choose the correct answer from the options given below :
The correct order of reactivity of the following benzyl halides towards reaction with KCN is :
Consider the following data :
\( \Delta_f H^\ominus (\text{methane, g}) = -X \text{ kJ} mol^{-1} \)
Enthalpy of sublimation of graphite \( = Y \text{ kJ mol}^{-1} \)
Dissociation enthalpy of \( H_2 = Z \text{ kJ mol}^{-1} \)
The bond enthalpy of C-H bond is given by :}
Given below are some of the statements about Mn and \( Mn_2O_7 \). Identify the correct statements.
A. Mn forms the oxide \( Mn_2O_7 \), in which Mn is in its highest oxidation state.
B. Oxygen stabilizes the Mn in higher oxidation states by forming multiple bonds with Mn.
C. \( Mn_2O_7 \) is an ionic oxide.
D. The structure of \( Mn_2O_7 \) consists of one bridged oxygen.
Choose the correct answer from the options given below :
The correct order of the rate of the reaction for the following reaction with respect to nucleophiles is :
\( CH_3Br + Nu^\ominus \rightarrow CH_3Nu + Br^\ominus \)
On heating a mixture of common salt and \( K_2Cr_2O_7 \) in equal amount along with concentrated \( H_2SO_4 \) in a test tube, a gas is evolved. Formula of the gas evolved and oxidation state of the central metal atom in the gas respectively are :
Given below are two statements :
Statement I : The correct order in terms of atomic/ionic radii is \( Al>Mg>Mg^{2+}>Al^{3+} \).
Statement II : The correct order in terms of the magnitude of electron gain enthalpy is \( Cl>Br>S>O \).
In the light of the above statements, choose the correct answer from the options given below :