ANALYTICAL CHEMISTRY
Important Past Questions:
State the colour of the precipitate formed when sodium hydroxide solution is added dropwise and then in excess to solutions containing the given ions:
i) Pb2+ ii) Fe2+ iii) Zn2+ iv) Fe3+ v) Cu2+ vi) Ca2+ [2004, 2011, 2016, 2018, 2019]
Give balanced equations for: Zinc oxide dissolves in NaOH. (2010, 2011, 2018)
Give balanced equations for: zinc is warmed with NaOH solution. (2004, 2011)
To a salt soln. "Y" a small quantity of NH4OH soln. is added slowly and then in excess. A pale blue precipitate is formed which dissolves in excess to form a clear inky blue soln. Identify the positive ion in the salt "Y".
OR Write the equation for copper [II] sulphate reacts with sodium/ammonium hydroxide and state the colour of the precipitate formed. (2005, 2013, 2015, 2016, 2019)
State the solution which gives a dirty green precipitate with sodium hydroxide. (2006, 2008, 2017, 2019)
How will you distinguish between ammonium hydroxide and sodium hydroxide using CuSO4 soln? (2017)
The salt solution which does not react with ammonium hydroxide:
A] Calcium Nitrate B] Zinc Nitrate C] Lead Nitrate D] Copper Nitrate (2018)
Give one test to distinguish between iron (III) chloride soln. and copper chloride soln. (2006)
Find the odd one with reasons (valency is not a criterion): Al(OH)3, Pb(OH)2, Mg(OH)2, Zn(OH)2. (2009)