2019 Paper 4 QP with Data

2019 A level H2 Chem Paper 4 QP 2019 A level H2 Chem Paper 4 QP

Brown ppt formed in colourless solution. Brown ppt dissolved in NH3(aq) to give a colourless solution. Brown ppt formed in colourless solution. Silver mirror is formed in the test tube

CO32−, SO42−, Cl−, Br−, I− To test for CO32−, add HCl(aq) to FA2 solution. CO32− will give effervescence of CO2 that gives a white ppt with limewater. To test for SO42−, add Ba(NO3)2(aq) to FA2 solution, followed by excess HNO3(aq). SO42− will give white ppt that is insoluble in excess HNO3(aq). To test for Cl−, Br−, I−, add AgNO3(aq) to FA2 solution, followed by excess NH3(aq). Cl− will give white ppt that is soluble in excess NH3(aq). Br− will give pale cream ppt that is partially soluble in excess NH3(aq). I− will give yellow ppt that is insoluble in excess NH3(aq).

No effervescence observed. Solution remains colourless No ppt formed. Solution remains colourless. White ppt formed in colourless solution. Upon adding excess NH3(aq), white ppt dissolves to give a colourless solution. Cl−

Mass of FA 2 + weighing bottle / g 13.846 Mass of residual FA2 + weighing bottle / g 5.888 Mass of FA 2 used / g 7.958 Time/ min T / C 0.0 29.8 1.0 29.4 2.0 29.2 3.5 23.4 4.0 22.0 5.0 21.6 6.0 21.6 7.0 21.9 8.0 22.0 9.0 22.4