2. When Conc. H2SO4 was added to an unknown salt present in a test tube, a brown gas (A) was evolved. This gas intensified when copper turnings were added in to test tube. On cooling gas (A) changed in to a colourless gas (B). (a)Identify the gases ‘A’ and ‘B’ (b)Write the equations for the reactions involved The gas ‘A’ is NO2 whereas ‘B’ is N2O4. XNO3 + H2SO4XHSO4 + HNO3 Salt (conc.) Cu + 4HNO3 (Conc.) Cu (NO3)2 + 2NO2 + 2H2O Blue Brown (A) 2NO2 (on cooling) N2O4 Colourless(B) 3. Arrange the following in the increasing order of the property mentioned. (i)HOCl, HClO2, HClO3, HClO4 (Acidic strength) (ii)As2O3, ClO2, GeO3, Ga2O3 (Acidity) (iii)NH3, PH3, AsH3, SbH3 (HEH bond angle) (iv)HF, HCl, HBr, HI (Acidic strength) (v)MF, MCl, MBr, MI (ionic character) Ans.(i)Acidic strength:HOCl<HClO2<HCIO3<HCIO4 (ii)Acidity: Ga2O3<GeO2<AsO3<CIO2 (iii)Bond angle: SbH3<AsH3<PH3<NH3 (iv)Acidic strength: HF<HCl<HBr<HI (v)Ionic character: MI<MBr<MCl<MF ASSIGNMENTS Very shot answer type questions: Which of NH3 and H3O+ has higher bond angle and why? Which of PH4I and PH4Cl is more stable and why? What is the basicity of H3PO3 and H3PO4?
2. When Conc. H2SO4 was added to an unknown salt present in a test tube, a brown gas (A) was evolved. This gas intensified when copper turnings were added in to test tube. On cooling gas (A) changed in to a colourless gas (B). (a)Identify the gases ‘A’ and ‘B’ (b)Write the equations for the reactions involved The gas ‘A’ is NO2 whereas ‘B’ is N2O4. XNO3 + H2SO4XHSO4 + HNO3 Salt (conc.) Cu + 4HNO3 (Conc.) Cu (NO3)2 + 2NO2 + 2H2O Blue Brown (A) 2NO2 (on cooling) N2O4 Colourless(B) 3. Arrange the following in the increasing order of the property mentioned. (i)HOCl, HClO2, HClO3, HClO4 (Acidic strength) (ii)As2O3, ClO2, GeO3, Ga2O3 (Acidity) (iii)NH3, PH3, AsH3, SbH3 (HEH bond angle) (iv)HF, HCl, HBr, HI (Acidic strength) (v)MF, MCl, MBr, MI (ionic character) Ans.(i)Acidic strength:HOCl<HClO2<HCIO3<HCIO4 (ii)Acidity: Ga2O3<GeO2<AsO3<CIO2 (iii)Bond angle: SbH3<AsH3<PH3<NH3 (iv)Acidic strength: HF<HCl<HBr<HI (v)Ionic character: MI<MBr<MCl<MF ASSIGNMENTS Very shot answer type questions: Which of NH3 and H3O+ has higher bond angle and why? Which of PH4I and PH4Cl is more stable and why? What is the basicity of H3PO3 and H3PO4?
805198203chemistry.docx