#1 Chlorophyll is a naturally occurring chelate compound in which central metal is
One such chelate is chlorophyll, the green pigment of plants. In chlorophyll the central ion is magnesium, and the large organic molecule is a porphyrin. The porphyrin contains four nitrogen atoms that form bonds to magnesium in a square planar arrangement.
#2 Which of the following is used in pencils?
A pencil is an implement for writing or drawing. It is a thin core of graphite well mixed with clay, inside a wooden body as protective casing that prevents the core from being broken.
#3 Which of the following metals forms an amalgam with other metals?
Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, tungsten, and tantalum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore.
#4 Chemical formula for water is
Water is a chemical substance with the chemical formula H2O. Water is a chemical substance with the chemical formula H2O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds.
#5 The gas usually filled in the electric bulb is
At the same time the pressure of Argon gas would almost prevent ‘evaporation’ of the filament. Modern bulbs are usually filled with a mixture of argon and nitrogen. More rarely, some bulbs are filled with pure argon, krypton or xenon. The earliest bulbs weren’t filled with any gas, but had vacuum inside.