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 (201​8)

  • 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)

List of All Important Equations and Observations for Analytical Chemistry