List of top Chemistry Questions

At 25°C molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 ohm^-1 cm² mol^-1 and at infinite dilution its molar conductance is 238 ohm^-1 cm² mol^-1. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is

What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20°C to 35°C ? (R = 8.314 J mol^-1 K^-1)

A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of electrode would be

What is the maximum numbers of electrons that can be associated with the following set of quantum numbers ?
n = 3, l=1 and m = -1

The value of Planck's constant is 6.63 × 10^-34 Js. The speed of light is 3 x 10¹⁷ nm s^-1. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of 6 x 10¹⁵ s^-1?

A reaction having equal energies of activation for forward and reverse reactions has

In which of the following exothermic reactions, the heat liberated per mole is the highest ?

According to Freundlich adsorption isotherm, the amount of gas adsorbed at very high pressure

Among the following four structures $I$ to $IV$, it is true that

The enthalpy of combustion of $2$ moles of benzene at $27^{\circ} C$ differs from the value determined in bomb calorimeter by

The number of enantiomers of the compound $CH _{3} CHBrCHBrCOOH$ is

Which of the following is not the product of dehydration of

Which of the following is less acidic among the given halogen compounds?

Figure shows a copper rod joined to a steel rod. The rods have equal length and equal crosssectional area. The free end of the copper rod is kept at $0^{\circ} C$ and that of steel rod is kept at $100^{\circ} C$. Find the temperature of the junction of the rod. Conductivity of copper $=390 W / m ^{\circ} C$. Conductivity of steel $=46 W / m ^{\circ} C$

Equal weights of $NaCl$ and $KCl$ are dissolved separately in equal volumes of solutions. Molarity of the two solutions will be :

When same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide solution, the ratio of volumes of hydrogen evolved is:

Strong reducing behaviour of $H_3PO_2$ is due to

For the dissociation reaction, $H _{2}( g ) \rightarrow 2 H ( g ) \quad \Delta H =162 Kcal$, heat of atomisation of $H$ is

How many grams of concentrated nitric acid solution should be used to prepare $250\, mL$ of $2 \cdot 0\, M HNO _{3}$ ? The concentrated acid is $70 \% HNO _{3}$.

The oxidation state of sulphur in $Na_2S_4O_6$ is

The alkali metals form salt-like hydrides by the direct synthesis at elevated temperature. The thermal stability of these hydrides decreases in which of the following order?

$NH_4Cl(s)$ 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

\(12\, g\) of a nonvolatile solute dissolved in \(108\, g\) of water produces the relative lowering of vapor pressure of \(0.1.\)The molecular mass of the solute is :

A compound with molecular mass $180$ is acylated with $CH_3COCl$ to get a compound with molecular mass $390$. The number of amino groups present per molecule of the former compound is

Bond distance in $HF$ is $9.17 \times 10^{-11}\, m$. Dipole moment of $HF$ is $6.10^4 \times 10^{-30}\, Cm$ . The percentage ionic character in $HF$ will be : (electron charge $= 1.60 \times 10^{-19}\, C$)