List of top Chemistry Questions

Match the following and choose the correct option given below. Compound/Type \quad Use A. Dry ice 1. Anti-knocking compound B. Semiconductor 2. Electronic diode or triode C. Solder 3. Joining circuits D. TEL 4. Refrigerant for preserving food
What is the degeneracy of the level of H-atom that has energy \( \frac{R_H}{9} \)?
\( \text{CH}_3\text{CH}_2\text{CH}_2\text{COCH}_3 \) reacts with \( \text{CH}_3 \text{MgBr} \) (one mole) followed by treatment with \( \text{H}_2 \text{O} \). The compound \( A \) formed in this reaction is
The reaction of zinc with \( \text{Cu}^{2+} \) produces the following. Entropy change \( \Delta S \) is given by \( 96.5 J \cdot \text{mol}^{-1} \cdot \text{K}^{-1} \).
What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition, \( n = 4 \) to \( n = 2 \) of He\(^+\) spectrum?
Consider the following reaction:
For the cell reaction \( 2\text{Cu}^{2+} + \text{Co} \rightarrow 2\text{Co}^{2+} + \text{Cu} \), \( E^\circ_{\text{cell}} \) is 1.89V. If \( E^\circ_{\text{Co}^{2+}/\text{Co}} \) is -0.28V, what is the value of \( E^\circ_{\text{Cu}^{2+}/\text{Cu}} \)?
A constant current of 30 A is passed through an aqueous solution of NaCl for a time of 1.00 h. What is the volume of Cl\(_2\) gas at STP produced?
An organic compound \( B \) is formed by the reaction of ethyl magnesium iodide with a substance \( A \), followed by treatment with dilute aqueous acid. Compound \( B \) does not react with PCC or PDC in dichloromethane. Which of the following is a possible compound for \( A \)?
Following compounds are respectively ... geometrical isomers
Select the correct statements(s)
End product of the following reaction is
In a Claisen condensation reaction (when an ester is treated with a strong base)
Which is more basic oxygen in an ester?
The product Y is
A near UV photon of 300 nm is absorbed by a gas and then re-emitted as two photons. One photon is red with wavelength of the second photon is
Acid hydrolysis of ester is first order reaction and rate constant is given by \[ k = \frac{2.303}{t} \log \frac{V_0 - V}{V_0 - V_t} \] where \( V_0 \), \( V_t \), and \( V_\infty \) are the volume of standard NaOH required to neutralise acid present at a given time, if ester is 50% neutralised then
The density of solid argon is 1.65 g per cc at 233°C. If the argon atom is assumed to be a sphere of radius \( 1.54 \times 10^{-8} \) cm, what percent of solid argon is apparently empty space? \( A_r = 40 \)
When 1 mole of CO\(_2\) occupying volume 10L at 27°C is expanded under adiabatic condition, temperature falls to 150 K. Hence, final volume is
Out of \( \text{H}_2 \text{SO}_4 \), \( \text{H}_2 \text{SO}_3 \), \( \text{H}_2 \text{S}_2 \text{O}_8 \), peroxy acids are
B can be obtained from halide by van-Arkel method. This involves reaction
Glycerol \( \text{C}_3 \text{H}_8 \text{O}_3 \) reacts with \(\text{HCl} \), the product A is obtained. What is the structure of A?
\( \gamma \) \( \text{H}_2 \text{O} \) → \( \text{Z} \) is identified as
Phenol is heated with phthalic anhydride in the presence of cone. H\(_2\)SO\(_4\). The product gives pink colour with alkaline ferric chloride. The product is
\( \text{NH}_4 \text{Cl} \) is heated in a test tube. Vapours are brought in contact with red litmus paper, which changes it to blue and then to red. It is because of