1. The most important ore of aluminum is
Explanation: Bauxite is the most important ore of aluminum which contains only 30–54% alumina, Al2O3.
2. Most soluble in water is:
c) Common salt
Explanation: Most soluble in water is Sugar.
3. Which of the following was to be discovered first in the chromospheres of the sun?
Explanation: The chromosphere (literally, "sphere of colour') is the second of the three main layers in the Sun's atmosphere and is roughly 2,000 kilometers deep. It sits just above the photosphere and just below the solar transition region. Helium, the lighter of the noble gases, was the first to be discovered. In fact, this element was first identified in the Sun's chromosphere rather than in the Earth.
4. Which of the following is in liquid form at room temperature?
Explanation: The only liquid elements at standard temperature and pressure are bromine (Br) and mercury (Hg). Although, elements caesium (Cs), rubidium (Rb), Francium (Fr) and Gallium (Ga) become liquid at or just above room temperature.
5.Sodium metal is kept under:
Explanation: Sodium is the metal stored in kerosene oil in order to prevent it from coming in contact with oxygen and moisture.
6. Quartz crystals normally used in quartz clocks etc. is chemically
a) Silicon Dioxide
b) Germanium Oxide
c) A mixture of Germanium Oxide and Silicon dioxide
d) Sodium Silicate
Explanation: The working of Quartz is usually by a crystal oscillator. The Silicon dioxides are the crystals which are piezoelectric and can be further used as speakers and microphones.
7. Which of the gas is not known as green house gas?
b) Nitrous oxide
c) Carbon dioxide
Explanation: The list of Green House Gases are as follows:
1) Water vapor
2) Carbon dioxide
4) Nitrous oxide
Hydrogen is not a Green House Gas.
8. Bromine is a
a) Black Solid
b) Red Liquid
c) Colourless Gas
d) Highly Inflammable Gas
Explanation: Bromine (Br), chemical element, a deep red noxious liquid, and a member of the halogen elements, or Group 17 (Group VIIa) of the periodic table.
9. The hardest substance available on earth is
Explanation: Diamond is regarded to be the hardest known material in the world.
10. The variety of coal in which the deposit contains recognizable traces of the original plant material is
Explanation: The variety of coal in which the deposit contains recognizable traces of the original plant material is peat