Chemistry bits for SSC, Banks and for all competitive exams

1.              What is the name of the scientist who stated that matter can be converted into energy?

               – Einstein

2.              The isotopes of chlorine with mass number 35 and 37 exist in which ratio?

   – 3 : 1

3.              A gas is found to have the formula (CO)n. Its vapour density is 70. What must the value of n be?

  – 5

4.              Which law directly explains the law of conservation of mass?

    – Avogadro’s law

5.              To whom the credit for the discovery of transuranic element goes?

– Seaborg

6.              How many moles are there is 140 g of Si (atomic mass of silicon is 28)?

– 5

7.              Which substance does not have a melting point?

– Glass

8.              By which a mixture of sand and naphthalene can be separated?

– sublimation

9.              An element X forms an oxide X03. What is the valency of X?

– 6

10.          Sodium carbonate crystals lose water molecules. What is this property called?

– Efflorescence

11.          By whom was the law of constant proportions enunciated?

– Proust

12.          What is the number of unpaired electrons in carbon atom?

– 2

13.          In an atom the order of filling up of the orbitals is governed by which principle?

– Aufbau principle

14.          Regarding the atom of a chemical element, magnetic quantum number refers?

– Orientation

15.          What are the atoms of the elements having same mass number but different atomic number called?

– isobars

16.          Rutherford’s scattering experiment related to the size of which thing?

– nucleus

17.          By whom was the absolute value of charge on electron determined?

 – R.A. Millikan

18.          Which property of the elements is a whole number?

– Atomic number

19.          Discovery of the nucleus of an atom was due to the experiment carried

out by which person?

– Rutherford

20.          What are the atoms of the elements which have same number of neutrons

called?

– Isotones

21.          Whose experiment proved that the speed of light was always the same?

–Michelson and Morley

22.          Which element has two electrons in the K-shell only?

– Helium

23.          What is Electromagnetic radiation with maximum wavelength?                                                          
          – Radio Waves

24.          Which nuclear particles responsible for holding all nucleons together?

– Mesons

25.          In which process, a nucleus spontaneously breaks down by emitting

radiation?

– Radioactive decay

26.          In atomic reactors, graphite is used as which name?

– Moderator

27.          Why is Cobalt-60 commonly used in radiation therapy?

–Because it emits gamma rays

28.          A radioactive substance has a half life of four months. Three-fourth of the

substance would decay in howmany months?

– 8 months

29.          What is a bond formed by the transfer of electrons between atoms of the

elements called?

– ionic bond

30.          What is a bond formed by sharing of electrons between atoms of the

elements called?

– covalent bond

  

31.          What is the maximum number of hydrogen bonds in a H2O molecule?

– 4

32.          Select the compound in which chlorine shows oxidation state + 7?

– HClO4

33.          What is the oxidation of two Cl atoms in bleaching powder Ca(OCl) Cl?

– +1,–1

34.          What is the Oxidation state of Mn in acidic KMnO4 change from?

– +7 to+2

35.          Why is Molten NaCl good conductor of electricity?

– Free ions

36.          What is the common oxidation state of alkali metals in the combined

state?

– +1

37.          What is the oxidation number and covalency-of sulphur in S8?

– 0, 2

38.          Starch iodide paper is used to test for the presence of which agent?

–Oxidising agent

39.          The pH of water at 25° C is 7. When it is heated to 100°C, what will the pH

of water?

– increases

40.          When Metal carbonate reacts with dilute acids, what does it forms?

– CO2

41.          The element common to all the acids is known as which name?

–Hydrogen

42.          What is the sum of pH and pOH in aqueous solution at 25°C?

– 14

43.          By what factor is a solution with pH = 2 more acidic than one with pH = 6 ?

– 104

44.          Red litmus paper is changed into blue in solution of which thing?

– Base

45.          What is formed by dissolution of base or acid in water?

– Exothermic

46.          Blue litmus paper is converted into red in solution of which thing?

– acid

47.          According to Arrhenius theory of an acid and base, an acid is a substance

that gives which ions in water?

– H+ ions

48.          What is the negative logarithmic value of hydrogen on called?

– pH

49.          What are the physical state of dispersion medium of a cloud ?

– Gas

50.          Vander Wall’s equation explains the behaviour of which gases?

– real gases