Dry ice is
Solid H2O
Solid CO2
Solid N2O4
Solid NH3
B.
Solid CO2
Solid CO2 sublimes directly to the vapour state (without converting into liquid) at-78°C under atmospheric pressure, hence used as a refrigerant and called dry ice or cardice. It is used to freeze metals, ice-cream and in laboratory as a coolant.
The magnetic nature of boron molecule is same as the magnetic nature of
nitrogen molecule
carbon molecule
unipositive nitrogen molecule
oxide ion
Which of the following is not a true alum?
Na2SO4.Al2(SO4)3.24H2O
MgSO4.Cr2(SO4)3.24H2O
K2SO4.Cr2(SO4)3.24H2O
(NH4)2SO4.Fe(SO4)3.24H2O
The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm-3 respectively. If the standard free energy difference is 1895 J mol-1, the pressure at which graphite will be transformed into diamond is
9.92 × 108 Pa
9.92 × 107 Pa
9.92 × 106 Pa
None of these
The order of covalent character of KF, KI, KCl is
KCl < KF < KI
KI < KCl < KF
KF < KI < KCl
KF < KCl < Kl