List of top Chemistry Questions

Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is Given : Molar mass of Mg is 24 g mol\(^{-1}\).
The total number of hydrogen bonds of a DNA-double Helix strand whose one strand has the following sequence of bases is _______ . $5^{\prime}-\mathrm{G}-\mathrm{G}-\mathrm{C}-\mathrm{A}-\mathrm{A}-\mathrm{A}-\mathrm{T}-\mathrm{C}-\mathrm{G}-\mathrm{G}-\mathrm{C}-\mathrm{T}-\mathrm{A}-3^{\prime}$
In Dumas' method for estimation of nitrogen 1 g of an organic compound gave 150 mL of nitrogen collected at 300 K temperature and 900 mm Hg pressure. The percentage composition of nitrogen in the compound is _______ % (nearest integer). (Aqueous tension at $300 \mathrm{~K}=15 \mathrm{~mm} \mathrm{Hg}$ )

Given below are the pairs of group 13 elements showing their relation in terms of atomic radius. $(\mathrm{B}<\mathrm{Al}),(\mathrm{Al}<\mathrm{Ga}),(\mathrm{Ga}<\mathrm{In})$ and $(\mathrm{In}<\mathrm{Tl})$ Identify the elements present in the incorrect pair and in that pair find out the element (X) that has higher ionic radius $\left(\mathrm{M}^{3+}\right)$ than the other one. The atomic number of the element (X) is

Pair of transition metal ions having the same number of unpaired electrons is :
Which of the following is the set of neutral oxides? (a) \( \text{Al}_2\text{O}_3, \text{Cl}_2\text{O}_7 \), b) \( \text{N}_2\text{O}, \text{CO} \)
In which of the following cases does manganese have a +7 oxidation state?
What technique is used to separate chloroform from aniline?
Which of the following has the highest \( K_b \) value?
What is the IUPAC name of phenyl isopentylether?
The disease is caused by a deficiency of riboflavin.
Layer's test is used for what purpose?
Find the pH of the solution if \( [\text{H}^+] = 2 \times 10^{-4} \, \text{mol/L} \).
Arrange in the order of conductivity: \[ \text{Na, Ag, Fe, Cu} \]
Which among the following acts as a Lewis acid? \[ A) \text{AlCl}_3, \quad B) \text{NH}_3, \quad C) \text{OH}^-, \quad D) \text{H}_2\text{O} \]
When toluene is treated with chromium oxide and acetic anhydride, followed by hydrolysis, what is the product formed?
Arrange in the order of dipole moment: \[ \text{NH}_3, \, \text{NF}_3, \, \text{H}_2\text{S}, \, \text{CHCl}_2 \]
What is the formula of lanthanoids with sulfur?
The reaction shown is: \[ \text{Phenol} + \text{CHCl}_3 + \text{NaOH} \rightarrow \text{Salicylaldehyde} \] What is the name of the above reaction?
Common oxidation state of Cr?
Which among the following has the highest molar elevation constant?
Find the rate constant at 310K if the initial concentration is 0.72 mol L$^{-1}$ and the final concentration is 1.44 mol L$^{-1}$ at 10 minutes.
Among the following, which one is incorrect? \[ \text{BrF}_5 \rightarrow \text{Trigonal bipyramidal}, \quad \text{SF}_4 \rightarrow \text{See saw}, \quad \text{NH}_3 \rightarrow \text{Pyramidal}, \quad \text{XeF}_4 \rightarrow \text{Square planar} \]
What is the order of the SN2 reaction for the compounds: \[ \text{2-methyl-2-bromo-butene}, \quad \text{2-bromo-butene}, \quad \text{1-bromo-butane} \]
Which of the following bond enthalpies is the least: \[ C = C, C = O, C \equiv N, C = N \]