SECTION - I (40 - Marks)
Q 1. (a) Answer the
questions below, relating your answers only to salts in the following list
Sodium Chloride, anhydrous calcium chloride, copper sulphate - 5- water.
(i) What name is given to the water in the compound copper sulphate -
(ii) If copper sulphate -5 - water is
heated, the water is driven off leaving anhydrous copper sulphate.
(A) What is the colour of anhydrous
(B) By what means, other than heating,
could you dehydrate copper sulphate -5-water and obtain anhydrous copper
(iii) What is deliquescence ?
(iv) Which one of the salts in the
given list is deliquescent ?
Q 1(b) State what you see when :
(i) a piece of moist blue litmus paper is placed in a gas jar of
(ii) a piece of moist red litmus paper is placed in a gas jar of ammonia .
(iii)Silver nitrate solution is added to dilute hydrochloric acid.
(iv)Zinc oxide is heated.
(v) A glowing splint is introduced into a gas jar containing oxygen.
Q 1 (c) Write correctly balanced
equations for the following reactions :
(i) Molten sodium and chlorine.
(ii) Nitrogen and oxygen when lightning strikes.
(iii) Iron and dilute sulphuric acid.
(iv) Decomposition of hypochlorous acid in sunlight.
(v) Action of heat on potassium nitrate.
Q 1(d) Water can be split into hydrogen and oxygen under suitable
The equation representing the change is :
--------------- 2H2(g) + O2(g).
(i) If a given experiment result in 2500 cm3 of hydrogen
being produced, what value of oxygen is liberated at the same time under
the same conditions of temperature and pressure?
(ii) The 2500 cm3 of hydrogen is
subjected to 2 1/2 times increases in pressure
(temperature remaining constant ). What volume will the hydrogen now
(iii) Taking the volume of hydrogen
calculated in (d) (ii), what change must be made in the kelvin (absolute)
temprature to return the volume to 2500 cm3 (pressure
Q 1 (e). The compound Na2B4O7.10H2O
is commonly known as borax. When litmus is added to a solution of borax
solution, it turns blue
(i) What can you say about the pH of borax solution?
(ii) Calculate the precentage of boron (B) in borax. (H = 1, B = 11, O =
16, Na = 23. Answer correct to 1 decimal place.)
Q 1 (f). (i) Sodium hydoxide
solution can be used to distinguish between iron (II) sulphate solution
and iron (III) sulphate solution because these solution give different
coloured precipitates with sodium hydroxide solutions. Give the colour of
the precipitate formed with :
(1) iron (II) sulphate solution ;
(2) iron (III) sulphate solution.
(ii) What will you see when barium chloride
solution is addded to iron (II) sulphate solution?
(iii) How will the action of dilute
hydrochloride acid on sodium carbonate and sodium sulphite enable you to
distinguish between these two compounds?
Q 1(g). Choosing only words from the
following list write down the appropriate words to fill in the blanks (i)
to (v) below :
anions, anode cathode, cations, electrode, electrolyte, nickel, voltameter.
To electroplate an article with nickel
requires an (i) ..............................which must be a solution
containing (ii)...................... ions. The article to be plated is
placed as the(iii).................................. of the cell in which
the plating is carried out .The (iv)............................ of the
cell is made from pure nickel. The ions which are attracted to the
negative electrodes and discharged are called (v)
Q 1(h).The following question result
to the Nitrogen Cycle.
(i) What are the soluble nitrogen compounds absorbed by the roots of
(ii) What kind of plants directly absorb nitrogen from the atmosphere ?
(iii) What term is applied to the conversion of atmosphere nitrogen to
useful compounds of nitrogen?
(iv) Compounds such as ammonium nitrate. urea and super - phosphate are
used to replace nitrogen and other elements loss from the soil as a result
of cultivation. What is the common name given to these compounds ?
(v) What insoluble substance is used in making superphosphate?