List of top Chemistry Questions

Aqueous solution of $Na_2S_2O_3$ on reaction with $Cl_2$ gives

Three moles of $PCl_5$, three moles of $PCl_3$ and two moles of $Cl_2$ are taken in a closed vessel. If at equilibrium the vessel has $1.5$ moles of $PCl_5$, the number of moles of $PCl_3$ present in it is

Which one of the following pairs is not correctly matched ?

A solution of colourless salt $H$ on boiling with excess $NaOH$ produces a non-flammable gas. The gas evolution ceases after sometime. Upon addition of $Zn$ dust to the same solution, the gas evolution restarts. The colourless salt(s) $H$

The correct statement(s) concerning the structures $E, F$ and $G$ is/are

When a concentrated solution is diluted by adding more water, molarity of the solution remains unchanged. Product of moles of a solute and volume is equal to the molarity.

The pH of a $0.001 \,M$ solution of $ HCl $ is

Resistance of a conductivity cell filled with a solution of an electrolyte of concentration 0.1 M is 100 $\Omega$. The conductivity of this solution is $1.29 S m^{-1}.$. Resistance of the same cell when filled with 0.2 M of the same solution is 520 $\Omega$. The molar conductivity of 0.02 M solution of the electrolyte will be:

The effect of temperature on reaction rate is shown by

$N _{2}(g)+3 H _{2}(g) \rightleftharpoons 2 NH _{3}(g)+22\, kcal$. The activation energy for the forward reaction is $50\, kcal$. What is the activation energy for the backward reaction?

Acid hydrolysis of sucrose is a

In the respect of the equation $ k=A{{e}^{-{{E}_{a}}/RT}} $ in chemical kinetics, which one of the following statements is correct?

For a first order reaction, to obtain a positive slope, we need to plot {where $[A]$ is the concentration of reactant $A$}

The following mechanism has been proposed for the reaction of NO with $Br_{2}$to form NOBr : $NO\left(g\right)+Br_{2} \left(g\right) \text{rightleftharpoons} NOBr_{2} \left(g\right)$ $NOBr \left(g\right)+NO \left(g\right) \to 2NOBr \left(g\right)$ If the second step is the rate determining step, the order of the reaction with respect to NO (g) is:

The radioactivity of a sample is $ {{R}_{1}} $ at a time $ {{T}_{1}} $ and $ {{R}_{2}} $ at times $ {{T}_{2}} $ . the half-life of the specimen is $T$, the number of atoms that have disintegrated at the time $ ({{T}_{2}}-{{T}_{1}}) $ is proportional to

An unknown element forms an oxide. What will be the equivalent weight of the element if the oxygen content is $20\%$ by weight?

$1$ mole of methyl amine on reaction with nitrous acid gives at $NTP$

1.520 g of hydroxide of a metal on ignition gave 0.995 g of its oxide. The equivalent weight of the metal is

During electrolysis of water the volume of $O _{2}$ liberated is $2.24\, dm ^{3}$. The volume of hydrogen liberated, under same conditions will be

Mass of acetic acid required to neutralize 100 cc of 0.1 N NaOH solution is

The number of moles of oxygen obtained by the electrolytic decomposition of $108 \,g$ water is

Number of atoms of $He$ in $100\, u$ of $He$ (atomic wt of $He$ is $4$) are

What is the time (in sec) required for depositing all the silver present in $125\, mL$ of $1\, M\,AgNO _{3}$ solution by passing a current of $241.25 A$ ?$ (IF =965000\, C)$

The ions $ {{N}^{3-}},{{O}^{2-}},{{F}^{-}},N{{a}^{+}}M{{g}^{2+}} $ are isoelectronic. Their ionic radii show

Fluorine molecule has bond order one. The number of electrons in the ant bonding molecular orbitals is two less than that in bonding molecular orbitals.