Chemistry MCQs

Notes:
When wood is burnt in a limited supply of oxygen, water and volatile materials present in it get removed and charcoal is left behind as the residue.

Notes:
Synthetic detergents are cleansing agents which can be used both in soft and hard water as they give foam even in hard water.

Notes:
The law of conservation of mass states that the mass of an isolated system will remain constant over time. It cannot be changed as a result of processes acting inside the system. This principle is equivalent to the conservation of energy: when energy or mass is enclosed in a system & none is allowed in or out, its quantity cannot otherwise change over time. The law states that mass can neither be created nor be destroyed, although it may be rearranged in space and changed into different types and categories of particles.

Notes:
Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted mopping up calcium ions.

Notes:
Stainless steel is an alloy of Iron with a minimum of 10.5% Chromium. Chromium produces a thin layer of oxide on the surface of the steel known as the passive layer. This prevents any further corrosion of the surface. Increasing the amount of Chromium gives an increased resistance to corrosion.

Notes:
Noonmati is a locality located in Guwahati, Assam in North East India. It is the place where Indian Oil Company commissioned its first oil refinery, the Guwahati Refinery on 1 January 1962.

Notes:
Garlic is known to cause bad breath and body odor, described as a pungent “garlicky” smell to sweat. This is caused by allyl methyl sulfide (AMS). The sulfur compound allicin, produced by crushing or chewing fresh garlic, produces other sulfur compounds: ajoene, allyl polysulfides, and vinyldithiins.

Notes:
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.

Notes:
The correct mass of Electron is 0. 00055 amu; Proton is 1.0078 amu and Neutron is 1.0083 amu. Kindly note mass of neutron is slightly more than that of Proton.

Notes:
99.985% of hydrogen atoms contain only one proton. This isotope is called protium( 1H1). Rest of the percentage of hydrogen atom contains two other isotopes, the one containing 1 proton and 1 neutron is called deuterium (1D2, 0.015%) and the other one possessing 1 proton and 2 neutrons is called tritium (1T3 ). The latter isotope is found in trace amounts on the earth.