Explanation:
According to the psychrometric chart at dry bulb temperature of [tex]21^{o}C[/tex] and RH 70%, the absolute humidity = 0.011 kg/kg dry air
Formula to calculate humid volume is as follows.
    [tex]\nu_{H} m^{3}/kg[/tex] dry air = [tex]\frac{22.41}{273}TK (\frac{1}{28.97} + \frac{1}{18.02}H)[/tex]
           = [tex](2.83 \times 10^{-3} + 4.56 \times 10^{-3} H) T K[/tex]
           = [tex](2.83 \times 10^{-3} + 4.56 \times 10^{-3} \times 0.011) \times 294[/tex]
            = 0.847 [tex]m^{3}/kg[/tex] dry air
Hence, humid volume of air is 0.847 [tex]m^{3}/kg[/tex] dry air.
Specific enthalpy of dry air  = specific heat capacity of dry air × dry bulb temperature
          = [tex]1.006 kJ/kg ^{o}C \times 21^{o}C[/tex]
          = 21.126 kJ/kg dry air
Hence, the specific enthalpy of the air is 21.126 kJ/kg dry air.
As per the psychrometric chart at given conditions wet bulb temperature = 17.5 [tex]^{o}C[/tex]
As per the psychrometric chart at given conditions dew point temperature = 15.5 [tex]^{o}C[/tex]
