Test : Chemistry - 1 - NDA MCQ

Metalloid, a chemical element with properties intermediate between those of typical metals and nonmetals.

Biogas consists mainly of methane (CH4) and carbon dioxide (CO2). Methane is a valuable form of gas, as it is an efficient energy carrier with a wide range of uses. The amount of CO2 that is produced corresponds to the amount of CO2 captured when the biomass was created.

Alkali metals have one electron in their outer shell so alkali metal can easily lose electrons.
 

Human Blood pH is regulated to stay within the narrow range of 7.35 to 7.45, making it slightly basic.

The reaction between baking soda (sodium bicarbonate) and vinegar (dilute acetic acid) generates carbon dioxide gas.

The chemical formula of Sodium Benzoate is C₇H₅NaO₂. It is widely used as food preservative.

Nitro chloroform is not an explosive substance.

The term endothermic process describes a process or reaction in which the system absorbs energy in the form of heat.

Cobalt oxide is added to glass to give it blue color.

When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt. The H(+) cation of the acid combines with the OH(-) anion of the base to form water.

Clark's method is a process for the large-scale removal of temporary hardness from water. Clark's process involves the addition of a controlled quantity of slaked lime .
 

The Isotopes are a set of nuclides/atoms having the same number of protons, but a different number of neutrons. In other words, the same atomic number having different atomic masses.

Brass gets discolored because of the presence of Hydrogen Sulphide in air.

Non-stick cookware is a common application, where the non-stick coating allows food to brown without sticking to the pan. Non-stick is often used to refer to surfaces coated with "Teflon."

Calcium hydroxide base is present in lime water.

• The pH of water at 25°c is 7. When it is heated to 100°C, the pH of water decreases to 6.14.
• On increasing the temperature of the water, the equilibrium would again move to lower the temperature.
• It would happen by absorbing the extra heat. 
• Hydrogen ions and hydroxide ions will remain at the same concentration in pure water and the water remains neutral even if its pH changes.

Acids in solution have a pH below 7.0, a sour taste, releases hydroxyl ions in water, turn litmus paper red and accept an electron.

There are two complementary definitions of acids and bases that are important: the Bronsted (or Bronsted-Lowry) definition: an acid is a proton (H+ ion) donor, and a base is a proton acceptor; the Lewis definition: an acid is an electron acceptor, and a base is an electron donor.

Ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Following the aphorism, \"like dissolves like\", ionic compounds dissolve in polar solvents, especially those that ionize, such as water and ionic liquids. They are usually appreciably soluble in other polar solvents such as alcohols, acetone. Solid ionic compounds cannot conduct electricity because there are no mobile ions or electrons present in the lattice.

A triple bond will always be found in a geometrically linear portion of the molecule. While a triple bond is the strongest type of bond, it is not three times stronger than a single bond because pi bonds are weaker than sigma bonds.

In H2O molecule, oxygen has 2 hydrogen attached & 2 lone pair of electrons, so it has tendency to form 4 hydrogen bonds.