CHEMISTRY LAB
ASSIGNMENT
BY
SAKTHIVEL
SIR
Why other acids rather than dil H2SO4 can not be
used in mohr’s salt titration ?
HCl and HNO3 are not used in the titration of Mohr's salt in place of sulfuric
acid because:
HCl is a mild reducing agent and it reacts with some of the indicator that is
KMnO4 solution so the final value of the indicator used come to be more than
the actual value disturbing the experiment.
HNO3 is also a powerful oxidizing agent along with KMnO4 so it also plays its
role in oxidation which causes a decline in the value of KMNo4 used.
As dilute sulfuric acid is ideal for redox titration because it is neither an oxidizing
agent and nor a reducing agent.
• Potassium Permanganate is a flexible and potent oxidant which can be
used by overt or indirect titration to classify many compounds. A special
value of Potassium Permanganate is that it acts as an indicator of its
own. Permanganate titration must be carried out in a heavy acid solution.
• It is reduced to brown coloured Mn2+ ion (in acidic media) at the end
point when used in redox titration, and the colour transition at the end
point can be quickly observed. Since the function of the indicator is to
detect endpoints, a separate indicator for permanganate titration is not
needed.
What property of the liquid causes viscosity?
• Cohesive forces between like molecules are responsible for a
liquid’s viscosity (resistance to flow) and surface tension (elasticity
of a liquid surface).