List of top Chemistry Questions

A gas absorbs a photon of $355 nm$ and emits at two wavelengths. If one of the emissions is at $680 nm$, the other is at:
The value of enthalpy change ($\Delta$H) for the reaction $C_{2}H_{5}OH_{\left(I\right)} + 3O_{2\left(g\right)} \to 2CO_{2\left(g\right)} + 3H_{2}O_{\left(I\right)}$ at $27^{\circ}C$ is $-1366.5 \,kJ \,mol^{-1}.$ The value of internal energy change for the above reaction at this temperature will be :
The correct order of electron gain enthalpy with negative sign of F, Cl, Br and I, having atomic number 9, 17, 35 and 53 respectively, is:
The molecular velocity of any gas is:
When r, P and M represent rate of diffusion, pressure and molecular mass, respectively, then the ratio of the rates of diffusion $(r_A/r_B)$ of two gases A and B, is given as:
Consider thiol anion $(RS^?)$ and alkoxy anion $(RO^?)$. Which of the following statements is correct ?
A 5.2 molal aqueous solution of methyl alcohol, $CH _{3} OH$ is supplied. What is the mole fraction of methyl alcohol in the solution?
$S_N2$ reaction readily occurs in
$\beta$-pleated sheet structure of protein shows maximum extension. Intermolecular hydrogen bonding is present in them.
The correct increasing order of reactivity for the following molecules towards electrophilic aromatic substitution is
The correct decreasing order of $pK_a$ is
When the same quantity of current is passed through $ {CuSO_4}$ and $ {AgNO_3}$ solution 2.7 g of silver is deposited. The amount of copper deposited is
The pOH of 0.0005 M sulphuric acid is
Bauxite is
Siderite is
Bond order in nitrogen molecule is
The radius ratio of a substance is 0.32. The coordination number of the substance is
Which of the following is pheromone?
Which of the following enzymes is present in animals like cow, buffaloes, etc. to digest compound like paper, cloth, etc.?
Which one of the following represents the correct ratio of the energy of electron in ground state of $H$ atom to that of the electron in the first excited state of $Li^{+}$ ?
Which one of the following has the lowest ionization energy?
The correct order of decreasing acidity of nitrophenols will be
The correct decreasing order of dipole moment in $ CH_{3}Cl,\,CH_{3} Br$ and $ CH_{3}F $ is
Term used for accumulation of non-degradable pollutants in higher trophic level is
Which ion has the largest radius?