List of top Chemistry Questions

The metal that shows highest and maximum number of oxidation state is:

Which of the following gives a positive test with ninhydrin ?

The correct order of ligands arranged in increasing field strength.

Given below are two statements :
Statement I: Nitration of benzene involves the following step –

Statement II: Use of Lewis base promotes the electrophilic substitution of benzene. In the light of the above statements.
Choose the most appropriate answer from the options given below :

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Cis form of alkene is found to be more polar than the trans form
Reason (R): Dipole moment of trans isomer of 2-butene is zero. In the light of the above statements.
Choose the correct answer from the options given below :

Which one of the following complexes will exhibit the least paramagnetic behaviour ? [Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27]

For the compounds:
(A) \( \text{H}_3\text{C} - \text{CH}_2 - \text{O} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \)
(B) \( \text{H}_3\text{C} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \)  
(C) \( \text{CH}_3 - \text{CH}_2 - \text{C} - \text{CH}_2 - \text{CH}_3 \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\ \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\ \)  

(D) \( \text{H}_3\text{C} - \text{CH} - \text{CH}_2 - \text{CH}_2 - \text{CH}_3 \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\ \)  
\(\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{OH}\ \)  
 
The increasing order of boiling point is: Choose the correct answer from the options given below:  

The statement(s) that are correct about the species O 2^– , F ^– , Na⁺ and Mg²⁺.
(A) All are isoelectronic
(B) All have the same nuclear charge
(C) O2^– has the largest ionic radii
(D) Mg²⁺ has the smallest ionic radii
Choose the most appropriate answer from the options given below :

The incorrect postulates of the Dalton's atomic theory are :
(A) Atoms of different elements differ in mass.
(B) Matter consists of divisible atoms.
(C) Compounds are formed when atoms of different element combine in a fixed ratio.
(D) All the atoms of given element have different properties including mass.
(E) Chemical reactions involve reorganisation of atoms.
Choose the correct answer from the options given below :

Number of molecules/species from the following having one unpaired electron is ________.
\( \text{O}_2, \, \text{O}_2^{1-}, \, \text{NO}, \, \text{CN}^{1-}, \, \text{O}_2^{2-} \)

The number of different chain isomers for \( \text{C}_7\text{H}_{16} \) is ______.

The de-Broglie's wavelength of an electron in the \( 4^{\text{th}} \) orbit is ______ \( \pi a_0 \). (\( a_0 = \text{Bohr's radius} \))

\( X \, \text{g} \) of ethylamine is subjected to reaction with \( \text{NaNO}_2/\text{HCl} \) followed by water; evolved dinitrogen gas which occupied \( 2.24 \, \text{L} \) volume at STP. \( X \) is ______ \( \times 10^{-1} \, \text{g} \).

The number of correct reaction(s) among the following is ________.

The correct order of first ionization enthalpy values of the following elements is :
(A) O (B) N (C) Be (D) F (E) B
Choose the correct answer from the options given below :

Identify the correct set of reagents or reaction conditions ‘X’ and ‘Y’ in the following set of transformation.

Identify the product in the following reaction :

The element which shows only one oxidation state other than its elemental form is :

Which of the following nitrogen containing compound does not give Lassaigne’s test ?

Given below are two statements :
Statement I : Acidity of -hydrogens of aldehydes and ketones is responsible for Aldol reaction.
Statement II : Reaction between benzaldehyde and ethanal will NOT give Cross – Aldol product.In the light of above statements, choose the most appropriate answer from the options given below.

Which among the following is incorrect statement?

One of the commonly used electrode is calomel electrode. Under which of the following categories calomel electrode comes ?

In the precipitation of the iron group (III) in qualitative analysis, ammonium chloride is added before adding ammonium hydroxide to :

What will be the decreasing order of basic strength of the following conjugate bases?
\( \text{OH}^-, \, \text{R}^-, \, \text{CH}_3\text{COO}^-, \, \text{Cl}^- \)