List of top Chemistry Questions

Assertion (A): Highest oxidation state of Mn is +7 in most of the transition elements.
Reason (R): Transition metals exhibit variable oxidation states.
Half-life (\( t_{1/2} \)) of a first order reaction is 1386 s. The value of rate constant is:
$[NiCl_4]^{2-}$ is paramagnetic while $[Ni(CO)_4]$ is diamagnetic even though both are tetrahedral. Why?
For which of the following ions will the magnetic moment ($\mu$) be maximum?
(A) Write the electronic configuration of the element with atomic number 24.
(B) Find the number of unpaired electrons in $Co^{2+}$ ion.
(C) Why is the range of oxidation states greater in the actinoid series compared to the lanthanoid series?
Write the structures of (A), (B), and (C) in the following reaction:
\[ C_6H_5NO_2 \xrightarrow{Fe/HCl} (A) \xrightarrow[\text{273 K}]{NaNO_2 + HCl} (B) \xrightarrow[\Delta]{H_2O/H^+} (C) \]
Write the structures of (A), (B), and (C) in the following reaction:
Reaction Scheme: \[ (C) \xleftarrow{\text{conc. } HNO_3} \text{Phenol} \xrightarrow{\text{dil. } HNO_3} (A) + (B) \]
What happens when aniline reacts with the following:
(A) Bromine water
(B) $(CH_3CO)_2O$ / Pyridine
(C) $HNO_2 + HCl (0^\circ - 5^\circ C)$
What is a peptide bond? Explain with an example.
Write the mechanism of bimolecular nucleophilic substitution reaction ($S_N2$) of alkyl halide.
Write the IUPAC nomenclature of the following organic compounds:
(A) $CH_3 - CH_2 - \overset{\text{O}}{\overset{||}{\text{C}}} - CH_2 - \underset{\text{CH}_3}{\underset{|}{\text{CH}}} - CH_3$
(B) $Ph - CH = CH - CHO$
Write the definition of electrode potential and cell electromotive force (emf).
Does the half-life of a first-order reaction depend on the initial concentration of the reaction? Explain.
The increasing order of reactivity of the following compounds in $S_N1$ reaction is:
Compounds:
A. $(CH_3)_3CBr$
B. $CH_3CH_2CH_2CH_2Br$
C. $(CH_3)_2CHCH_2Br$
D. $CH_3CH(Br)CH_2CH_3$
If the rate law of a reaction is Rate $= K[A]^2 [B]^0$, then what will be the order of the reaction?
Assertion (A): D(+)-Glucose is dextrorotatory in nature.
Reason (R): (+) represents dextrorotatory nature and D represents its configuration.
Which of the following Grignard Reagent will be used to prepare cyclohexylmethanol when treated with methanal?
Which of the reactions is used in the conversion of a ketone into hydrocarbon?
What happens when acidic solution of potassium permanganate is allowed to stand for sometime ? Give the equation involved. What is this type of reaction called ?
Why Cr has higher melting point than Mn ?
Why transition metals act as good catalyst ?
Name a member of the lanthanoid series
(I) which exhibits +4 oxidation state
(II) which exhibits +2 oxidation state.
Write the ionic equations for the oxidising action of potassium permanganate for its reaction with \(I^-\) in both acidic and alkaline solutions.
From the given data of \(E^{\circ}\) values, answer the following questions :
(I) Why \(E^{\circ}_{M^{2+}/M}\) show irregular trend in the above values ?
(II) Why is \(E^{\circ}_{Cu^{2+}/Cu}\) value exceptionally positive ?
(III) Why \(E^{\circ}_{Mn^{2+}/Mn}\) value is highly negative ?
Draw the structure of 'X' in the following reaction: