Chemistry · NDA previous year questions

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2010 27 questions

Q622010 · 22 Aug 2010
By which one among the following mechanism, soap removes dirt (soil) from cloth ?
1. A.Soap dissolves the soil as such
2. B.Soap reacts with soil and converts them into soluble silicates
3. C.Soap takes away the oily part of the soil and thus separates the soil from the cloth
4. D.The soap molecules bind with the soil, lift the soil and keep it suspended which can then be rinsed away
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Answer: D
Q632010 · 22 Aug 2010
Which one among the following statements is not correct about graphite ?
1. A.It is the most stable allotrope of carbon
2. B.It is an electrically conducting material
3. C.Crystalline spherical beads of graphite have very good lubricating property under dry conditions
4. D.It is the highest grade of coal
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Answer: D
Q642010 · 22 Aug 2010
Which one among the following is not a property of salt ?
1. A.Salts have ordered packing arrangements called lattices
2. B.Salts have low melting points but high boiling points
3. C.Salts are brittle
4. D.Salts conduct electricity when dissolved in water or even in the molten state
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Answer: B
Q652010 · 22 Aug 2010
Which among the following statements with regard to pH scale is/are correct ? 1. It is a logarithmic scale 2. The scale is limited to 0—14 because the ionic product of water is about $1 0^{- 14}$ 3. The lower the value of pH the greater is the acidity of the solution Select the correct answer using the code given below :
1. A.1 and 2 only
2. B.1, 2 and 3
3. C.1 and 3 only
4. D.2 only
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Answer: B
Q662010 · 22 Aug 2010
An oxidizing agent is a substance which :
1. A.increases the oxidation number of an element in a given substance
2. B.decreases the oxidation number of an element in a given substance
3. C.is oxidized itself in an oxidation-reduction reaction
4. D.loses electrons in an oxidation-reduction reaction
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Answer: A
Q672010 · 22 Aug 2010
Neutral water with pH about 7 becomes slightly acidic when aerated. This is because :
1. A.oxygen from air is dissolved in the water which makes the water acidic
2. B.dirt, which get contaminated with the water during aeration makes the water acidic
3. C.ultraviolet radiation dissociates water molecules and makes water acidic
4. D.carbon-dioxide from air is dissolved
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Answer: D
Q682010 · 22 Aug 2010
Which one of the following statements is not correct ?
1. A.Diesel burns with air in a diesel engine at a high temperature at which nitrogen and oxygen from air can combine whereas petrol burns at a lower temperature at which nitrogen and oxygen can not combine
2. B.Diesel contains some nitrogenous compounds whereas petrol does not
3. C.Nitrogen from air is easily dissolved in diesel but it is not soluble in petrol
4. D.A catalyst is used in diesel engines which contains nitrogen whereas petrol engines do not need such catalysts
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Answer: C
Q692010 · 22 Aug 2010
Consider the following statements with regard to the properties of water : 1. Water is a good solvent for ionic compound but poor solvent for covalent compound 2. Water is a good solvent for covalent compound but poor solvent for ionic compound 3. Water has maximum density at the temperature 277 K Which of the statements given above are correct ?
1. A.1 and 3 only
2. B.2 and 3 only
3. C.1 and 2 only
4. D.1, 2 and 3
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Answer: A
Q702010 · 22 Aug 2010
Calcium carbonate is naturally available as limestone and can also be synthesized from quick lime. It is seen that the composition of the elements in both the natural and synthetic calcium carbonate are same. The validity of which one among the following laws is confirmed by this observation ?
1. A.Law of conservation of mass
2. B.Law of definite proportion
3. C.Law of multiple proportion
4. D.Avogadro’s law
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Answer: B
Q712010 · 22 Aug 2010
When aqueous solutions of two salts are mixed, the third salt formed may appear as a solid precipitates or a clear solution depending upon the solubility of its ions. It is observed that all salts of Na, K, $N H_{4}$ are soluble. All nitrates and bicarbonates are also soluble. All halides (chlorides, bromides, iodides) are soluble except those of Ag, Hg (I) and Pb. All sulphates are soluble except those of Ag, Ca, Ba and Pb. Which one among the following combinations of solutions will produce a solid precipitate ?
1. A.Sodium sulphate and barium chloride
2. B.Magnesium sulphate and barium bicarbonate
3. C.Lithium iodide and barium chloride
4. D.Ammonium sulphate and potassium bromide
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Answer: A
Q732010 · 22 Aug 2010
Iodized salt is a :
1. A.mixture of potassium iodide and common salt
2. B.mixture of molecular iodine and common salt
3. C.compound formed by combination of potassium iodide and common salt
4. D.compound formed by combination of molecular iodine and common salt
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Answer: A
Q742010 · 22 Aug 2010
Which one among the following is a chemical process?
1. A.Distillation of sea (salty) water
2. B.Crystallization of impure salt (NaCl)
3. C.Production of iodine ( $I_{2}$ ) from sea-weeds
4. D.Sublimation of iodine ( $I_{2}$ )
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Answer: C
Q872010 · 22 Aug 2010
Two pieces of metallic wire having equal length and equal volume placed in air have different resistances. The two wires must :
1. A.have different cross sections
2. B.have different temperatures
3. C.be of different materials
4. D.be of same density
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Answer: C
Q902010 · 22 Aug 2010
A hollow metal ball carrying an electric charge produces no electric field at points :
1. A.outside the sphere
2. B.on its surface
3. C.inside the sphere
4. D.only at the centre
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Answer: C
Q942010 · 22 Aug 2010
A heavy ball is suspended as shown in the figure given above. A quick jerk on the lower string will break that string but a slow pull on the lower string will break the upper string. The first result occurs because :
1. A.the force is too small to move the ball
2. B.air friction holds the ball back
3. C.of action and reaction
4. D.the ball has inertia
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Answer: D
Q1002010 · 22 Aug 2010
Metal pipes used to carry water sometimes burst in the winter. This is because :
1. A.water expands when it freezes
2. B.metal contracts more than water
3. C.outside of the pipe contracts more than inside
4. D.metal expands more than water
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Answer: A
Q582010 · 18 Apr 2010
Among the following elements, which one is essential for the transmission of impulses in the nerve fibre?
1. A.Calcium
2. B.Iron
3. C.Sodium
4. D.Zinc
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Answer: C
Q672010 · 18 Apr 2010
Which one of the following statements is correct?
1. A.Only electrons reside inside the nucleus of an atom
2. B.Both electrons and protons reside inside the nucleus of an atom
3. C.Only neutrons reside inside the nucleus of an atom
4. D.Both protons and neutrons can reside inside the nucleus of an atom
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Answer: D
Q882010 · 18 Apr 2010
The metal atom, which is present in superphosphate, is
1. A.sodium (Na)
2. B.potassium (K)
3. C.calcium (Ca)
4. D.magnesium (Mg)
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Answer: C
Q902010 · 18 Apr 2010
Which one among the following metals is more reactive than hydrogen?
1. A.Mercury
2. B.Copper
3. C.Silver
4. D.Tin
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Answer: D
Q962010 · 18 Apr 2010
Which one of the following is a transition metal?
1. A.Aluminium (Al)
2. B.Manganese (Mn)
3. C.Magnesium (Mg)
4. D.Calcium (Ca)
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Answer: B
Q972010 · 18 Apr 2010
Which one of the following gases, present in the air near the surface of the Earth, has maximum concentration?
1. A.Oxygen ( $O_{2}$ )
2. B.Hydrogen ( $H_{2}$ )
3. C.Nitrogen ( $N_{2}$ )
4. D.Methane ( $C H_{4}$ )
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Answer: C
Q982010 · 18 Apr 2010
Which one of the following elements will replace hydrogen from acids to form salts?
1. A.Sulphur (S)
2. B.Silicon (Si)
3. C.Zinc (Zn)
4. D.Phosphorus (P)
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Answer: C
Q992010 · 18 Apr 2010
Which of the following represent a chemical change? 1. Magnetization of iron 2. Condensation of liquid 3. Burning of fuel 4. Rusting of iron Select the correct answer using the code given below: Code:
1. A.1 and 2
2. B.2 and 3
3. C.3 and 4
4. D.1 and 4
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Answer: C
Q1002010 · 18 Apr 2010
Which one among the following is the correct order of reactivity of the elements?
1. A. $Cu > Mg > Zn > Na$
2. B. $Na > Zn > Mg > Cu$
3. C. $Cu > Zn > Mg > Na$
4. D. $Na > Mg > Zn > Cu$
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Answer: D