Multiple Choice QuestionsDue to the presence of an unpaired electron free radicals are
cations
anions
chemically inactive
chemically reactive
Ionic radii are
inversely proportional to effective nuclear charge
inversely proportional to square of effective nuclear charge
directly proportional to effective nuclear charge
directly proportional to square of effective nuclear charge
Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species ?
Cl < F < S < O
O < S < F < Cl
S < O < Cl < F
F < Cl < O < S
Among NH3, HNO3, NaN3 and Mg3N2 the number of molecules having nitrogen in negative oxidation state is
1
2
3
4
Oxygen and sulphur both are the member of same group in periodic table but H2O is liquid while H2S is gas because
molecular weight of water is more
electronegativity of sulphur is more
H2S is weak acid
water molecules are having weak hydrogen bonds between them
D.
water molecules are having weak hydrogen bonds between them
Both O and S belong to the same group but H2O is a liquid while H2S is a gas. This can be explained on the basis of electronegativity.
In water due to the high electronegativity of oxygen, hydrogen bonds are formed. As a result the molecules of H2O get associated together, hence water exists as liquid at room temperature. On the other hand, the electronegativity of S is less and therefore, hydrogen bonding in H2S is almost negligible.
As a result of which molecules of H2S are not associated and H2S exists as a gas at room temperature.
The pair of elements having approximately equal ionisation potential is
Al, Ga
Al, Si
Al, Mg
Al, B
On adding 1 g arsenic to 80 g benzene, the freezing' point of benzene is lowered by 0.19°C. The formula of arsenic is
As
As2
As3
As4
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