SCHOLASTIC APTITUDE TEST 2000
|Time: 1 Hour
(1) Answer must be written either in
English or the medium of instruction of the candidate in high
(2) There will be no negative marking
(3) Use of calculators or graph papers
is not permitted
(4) There are SIX Questions. Answer all
I. Differentiate the following:
(10x2 =20 Marks)
- orbit - orbital
- rayon - nylon
- strong acid - concentrated
- polypeptides -
- periodicity - periodic
- acidity - basicity
- solution - colloid
- normal salt - acid salt
- vanderwaals forces -
- hardening - annealing
II. Write the balanced Chemical
Equations for following chemical changes: (5x1=5
- Photographic film is exposed
- Lightening strucks the
- Burning magnesium ribbon is
inserted into a jar of carbondioxide.
- Lime water is exposed to air.
- Red hot Iron interacts with
III. Explain the following
Facts: (10x2 = 20 Marks)
(Write the chemical equations
- Formation of F-(g)
from F(g) is exothermic where as formation of O2-(g)
from O(g) is endothermic.
- Acetylene reacts with
ammonical silver nitrate where as ethylene does not react
with this reagent.
- HF is weaker than HCl is
- In the electroplating of an
article, the metal to be plated on the article is made as
anode and article to be electroplated is placed at the
- Pure NaCl is precipitated
when HCl is bubbled through concentrated solution of
- MgSO4 crystallises
with greater number of molecules of water of
crystallisation than CaSO4.
- CO2 is gas where
as SiO2 is solid at room temperature.
- Across a period from left to
right atomic size should increase as the number of
electrons is increasing. But atomic size decreases.
is used as oxidising agent in H2SO4
medium. Can we use HCl as acidic medium?
- An aqueous solution of I2
becomes colourless on adding little NaOH solution to it.
IV. Fill in the blanks: (5x1
= 5 Marks)
- The volume of steam produced
when a mixture of 22.4 litres of Hydrogen and 22.4 litres
of oxygen is ignited at 1000C
- In nuclear reactions there is
conservation of ______________ and ____________ for
reactants and products.
- Half life periods of two
bromine nuclei 80Br and 80Br are 4.4
hr and 18 minutes respectively. These two nuclei are
- Aminoacids are water soluble
and have high melting points due to ______________.
- Iron is independently
converted into FeCl2 and FeCl3 by
reacting with _________ and ____________ respectively.
V. Multiple choice. Each
question has one or more answers. Indicate
the correct answer by A,B,C,D. (5x1 = 5 Marks)
- Which of the following
equilibria is (are) affected by pressure change
- Atom X (with 1 valence
electron), Atom Y (with 3 valence electrons) Atom Z (with
7 valence electrons) belong to same period in the
periodic table. The correct formula(e) of compounds
formed from these atoms are.
- If 92U235
undergoes decay only by emitting a and b particles, the possible product(s) of decay
Is responsible for the colour of the dye
forms chemical bonds between dye and fibre
intensifies the colour of the dye
all the above
- When a perfect gas is made to
expand into vacuum at constant temperature
its internal energy increases
internal energy decreases
decrease in internal energy is followed by its
conversion is to liquid
no change in internal energy
VI. Solve the following: (5
- An experiment to measure
Avogadros number involves the collection of a beam
of alpha particles to which electrons are added to give
neutral helium. Suppose that for a particular run it
takes a number of electrons equivalent to 6.40x10-5
coulomb/sec to neutralise the beam, and that after 24
hours of collection 1.14x10-4 g of neutral
helium are collected. From this data, determine Avogadros
number. The charge on one electron is 1.602x10-19
coulombs. (24 hours is equivalent to 86,400 sec) 3M
- An element of atomic weight X
consists of two isotopes of Mass number (X-1) and (X+2)
what is the percentage abundance of heavier isotope. 2M