Aqueous solution of ferric chloride is acidic due to
ionization
polarization
dissociation
hydrolysis
The correct order of heat of formation of halogen acids is
HI > HBr > HCl > HF
HF > HCl > HBr > HI
HCl > HF > HBr > HI
HCl > HBr > HF > HI
The hydroxide insoluble in NH4OH + NH4Cl is
Al(OH)3
Ca(OH)3
Zn(OH)2
Mg(OH)2
A.
Al(OH)3
When aluminium salt reacts with NH4OH, then a white ppt of Al(OH)3 is obtained which is insoluble in excess of NH4OH solution.
AlCl3 + 3NH4OH → 3NH4Cl + Al(OH)3
The hydroxide of iron, chromium and aluminium are insoluble in excess of NH4OH solution.
Precipitate of AgCl is soluble in liquid NH3 the compound forms
Ag(NH4)2OH
Ag(NH4)2Cl
Ag(NH3)2OH
Ag(NH3)2Cl
In qualitative analysis, in III group NH4Cl is added before NH4OH because
to increase the concentration of NH ions
to increase the concentration of Cl- ions
to reduce the concentration of OH- ions
to increase the concentration of OH- ions