Chem quiz

Q.1 The inert gases are ____ in water
      A. sparingly soluble
      B. insoluble
      C. soluble

      D. None of these

Explanation :-

Noble gases are non-polar substances, so the only form of intermolecular forces that they have are London dispersion forces.

When a polar molecule (with dipole-dipole forces) dissolves in water, the slightly positive end of water is attracted to the slightly negative end of the other molecule.
So, the molecules will be separated from each other because they have a greater attraction with water.

However, when noble gases are dissolved in water, they only dissolve very slightly.
Noble gases only have London dispersion forces, so there's very little attraction between water and these noble gases.

They still can dissolve, but only very little, because some water molecules will be able to form dipole-induced dipole attractions with the noble gas atom.

This is when the positive side of a water molecule induces a negative charge on the noble gas atom (or vice versa), creating a slight attraction.

            

Answer:-A

Q.2 The molecular formula of phosphorous is
      A. P1
      B. P2
      C. P3
      D. P4

Answer:-D

Q.3 The method of concentrating the ore which makes use of the difference in density between ore            and impurities is called
      A. liquation
      B. leaching
      C. levigation

      D. magnetic separation

Answer: Option C

chem quiz

Q.1. Water drops are spherical because of ?
        A.viscosity
        B.density
        C.polarity

        D.surface tension

Explanation:-

This is due to the surface tension of the liquid.

The cohesive force between the liquid molecules is responsible for the phenomenon called surface tension.

The cohesive forces between molecules in a liquid are shared with all neighboring molecules. Those on the surface, they have no neighboring molecules above and, thus, exhibit stronger attractive forces upon their nearest neighbors on and below the surface.

Surface tension could be defined as the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of the water molecules.

Answer:-D

Q.2 Which one of the following metals does not react with water to produce Hydrogen?
       A.Cadmium
       B.Lithium
       C.Potassium
       D.Sodium

Answer:A

Q.3 Aspirin is
       A.acetyl salicylic acid
       B.sodium salicylate
       C.methyl salicylate
       D.ethyl salicylate

Answer:A

chem quiz

Q.1 The Mercury and Sodium street lamps light up because of
       A.atomic absorption
       B.atomic emission
       C.electron absorption
       D.electron emission

Explanation:-

The mercury vapor lamp is a high intensity discharge lamp. It uses an arc through vaporized mercury in a high pressure tube to create very bright light directly from it's own arc. This is different from fluorescents which use the mercury vapor arc to create a weaker light that mainly creates UV light to excite the phosphors. The "Merc" as it is known has been a workhorse for society; lighting streets, factories and large areas for over 100 years.

Sodium Lamps were first produced commercially by Philips in Holland in 1932. There are two kinds of sodium lights: Low Pressure (LPS) and High Pressure (HPS). These lamps are mostly used for street lighting as well as industrial uses.

The lamp works by creating an electric arc through vaporized sodium metal. Other materials and gases are used to help start the lamp or control its color.

Answer:-atomic emission