List of top Chemistry Questions

Which of the following oxidation states is common for all lanthanides ?

Which one of the following noble gases, is least polarisable?

Which is the correct increasing order of ionization energies?

What is the structure of $ {{H}_{2}}O $ ?

van der Waals gas equation for n mole gas is:

The most stable carbonium ion among these is:

The catalyst used in Ostwalds method nitric acid preparation, is:

The chemical formula of lunar caustic is:

Solid $ PC{{l}_{5}} $ exists as:

Reaction of ethyne with HCN, in the presence of $ Ba{{(CN)}_{2}} $ is:

How many isomeric forms of $ {{C}_{7}}{{H}_{9}}N $ contain a benzene ring?

$ CH\equiv \equiv CH\xrightarrow[{{H}_{2}}S{{O}_{4}}]{{{H}_{2}}O/H{{g}^{2+}}}X\xrightarrow{LiAl{{H}_{4}}}Y\xrightarrow{{{P}_{4}}/B{{r}_{2}}}Z, $ Here Z is:

Pi-bond (Ti-bond) is formed:

What is packing fraction of $ {}_{26}F{{e}^{56}} $ ? (At. mass = 55.92066)

Milk is a colloid in which:

An element is in $ {{M}^{3+}} $ form. Its electronic configuration is $ [Ar]\,4{{s}^{1}} $ . What is the atomic number of element?

Green vitriol is:

Which of the following has smallest size?

The number of neutrons in the element ${ }_{4} Be ^{9}$ is :

Standard electrode potentials for Fe electrode are given as $Fe^{2+}+2e^{-} \rightarrow Fe ; E^{o}=-0.44 V$ $Fe^{3+}+e^{-} \rightarrow Fe^{2+}; E^{o}=+0.77 V$ $ Fe^{2+}, Fe^{3+}$ and Fe blocks are kept together then

Change in enthalpy for reaction 2H2O2(l) → 2H2O(l) + O2(g) If heat of formation of H2O2(l) and H2O(l) are – 188 & – 286 KJ/mol respectively : -

When 1 mol gas is heated at constant volume temp. is raised from 298 to 308 K. Heat supplied to the gas is 500 J. Then which statement is correct : -

The coordination number of Fe(II) in oxyhaemoglobin is

One mole of fluorine is reacted with two moles of hot and concentrated KOH. The products formed are KF, $H_2O$ and $O_2$ The molar ratio of KF, $H_2O$ and $O_2$ respectively is

Which one of the following is a diamagnetic ion ?