Which one of the following statements is not correct?
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
Diesel contains some nitrogenous compounds whereas petrol does not
Nitrogen from air is easily dissolved in diesel but it is not soluble in petrol
A catalyst is used in diesel engines which contains nitrogen whereas petrol engines do not need such catalysts
C.
Nitrogen from air is easily dissolved in diesel but it is not soluble in petrol
A mixture containing SiO2, NaCl, and NH4Cl is taken for separating the constituents. The suitable steps required for this are:
Sublimation-dissolution-filtration-crystallization
Dissolution-filtration-crystallization-distillation
Sublimation-evaporation-dissolution-decomposition
Dissolution-distillation-decomposition evaporation
Consider the following statements with regard to the properties of water:
Which of the statements given above are correct?
1 and 3 only
2 and 3 only
1 and 2 only
1, 2 and 3
An oxidizing agent is a substance which:
increases the oxidation number of an element in a given substance
decreases the oxidation number of an element in a given substance
is oxidized itself in an oxidation-reduction reaction
loses electrons in an oxidation reduction reaction
Which among the following statements with regard to pH scale is/are correct?
Select the correct answer using the code given below:
1 and 2 only
1, 2 and 3
1 and 3 only
2 only
When aqueous solutions of two salts are mixed, the third salt formed may appear as a solid precipitate or a clear solution depending upon the solubility of its ions. It is observed that all salts of Na, K, NH4 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?
Sodium sulphate and barium chloride
Magnesium sulphate and barium bicarbonate
Lithium iodide and barium chloride
Ammonium sulphate and potassium bromide
Which one among the following statements is not correct about graphite?
It is the most stable allotrope of carbon
It is an electrically conducting material
Crystalline spherical beads of graphite have very good lubricating property under dry conditions
It is the highest grade of coal
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 is the same. The validity of which one among the following laws are confirmed by this observation?
Law of conservation of mass
Law of definite proportion
Law of multiple proportions
Avogadro's law
Which one among the following is not a property of salt?
Salts have ordered packing arrangements called lattices
Salts have low melting points but high boiling points
Salts are brittle
Salts conduct electricity when dissolved in water or even in the molten state
Neutral water with pH about 7 becomes slightly acidic when aerated. This is because:
oxygen from air is dissolved in the water which makes the water acidic
dirt, which gets contaminated with the water during aeration makes the water acidic
ultraviolet radiation dissociates water molecules and makes the water acidic
carbon-dioxide from air is dissolved