List of top Chemistry Questions

A sample of water has no fluoride (F) ions in it. What is the maximum limit (in $mg~L^{-1}$) of soluble fluoride salt to be added to this water to convert it into safe drinking water?

Dihydrogen reacted with elements of atomic number 15, 19 and 40 to form respective hydrides. The type of these hydrides respectively are

Which of the following does not exist?

Consider the following reactions \[ Al(s)+HCl(aq)\rightarrow X+A\uparrow \] \[ Al(s)+NaOH(aq)\rightarrow Y+B\uparrow \] Which of the following is are correct? I. Y is water soluble II. X is not soluble in water III. Both A and B are same

The correct order of hydration enthalpy of ions of Li, Na, Mg, Ca is

The pair of s-block metals which do not form solid hydrogen carbonates is

Which one of the following molecules has maximum number of lone pairs of electrons?

At $T(K)$ the kinetic energy of one mole of an ideal gas is 3735 J. If its pressure is 1 atm, the volume of gas is ($R = 8.3~J~mol^{-1}K^{-1}$)

What is the pH of $10^{-2}M$ aqueous solution of aniline at 298 K?}

Observe the following reaction and identify the correct relationships from the following \[ xP_4(s)+yOH^{-}(aq)+zH_2O(l)\rightarrow aPH_3(g)+bH_2PO_2^{-}(aq) \] I. $x+y+z=6$ II. $x=a$ III. $x+y+z=3+a+b$ IV. $a-z+b=1$

Identify the reaction in which the hybridization of the underlined atom is changed

What is the enthalpy change (in $kJ~mol^{-1}$) for the following reaction? \[ CCl_4(g)\rightarrow C(g)+4Cl(g) \]

In a cathode ray experiment hydrogen gas was subjected to very low pressure and high voltage. The $\frac{e}{m}$ of cathode rays liberated was $-x~C~kg^{-1}$. In the second experiment helium gas was used under the same experimental conditions. What is the $\frac{e}{m}$ $(in~C~kg^{-1})$ of cathode rays liberated in the second experiment?}

The atomic numbers of four elements A, D, E, G are 4, 7, 8, 12 respectively. The decreasing order of electronegativity of these elements is

Consider the following ions

. The largest cation and largest anion are respectively}

The work function $(W_0)$ of metals A, B and C is 2.25, 2.42 and 3.7 eV respectively. These metals were irradiated with light of wavelength 400 nm. Identify the metals from which photoelectrons are emitted $(h = 6.6 \times 10^{-34} Js; c = 3 \times 10^8 ms^{-1}; 1 eV = 1.6 \times 10^{-19} J)$

The correct order of acidic strength is: \[ CH_3COOH,\quad ClCH_2COOH,\quad Cl_2CHCOOH,\quad Cl_3CCOOH \]

The number of stereoisomers possible for the compound \(CH_3CH(OH)CH(OH)CH_3\) is:

The standard electrode potentials are: \[ E^\circ_{Cu^{2+}/Cu}=+0.34V \] \[ E^\circ_{Zn^{2+}/Zn}=-0.76V \] The standard emf of the Daniell cell is:

The major product obtained when phenol is treated with bromine water is:

Among the following species, which one has the highest bond order according to Molecular Orbital Theory?

A first-order reaction has a half-life of 20 minutes. The time required for \(87.5%\) completion of the reaction is:

The incorrect statement regarding d-block elements is:

The value of pH for a \(10^{-8}\,M\) HCl solution at \(25^\circ C\) is closest to:

Which of the following compounds exhibits the maximum hydrogen bonding in the liquid state?