CAPF (AC) 2022 (Paper-1) (Question 1-50)

Time taken by A to complete the work

= (15 × 10) / (15 - 10)

= 30 days

Difference between first and last number.

= 4 × [(Average of first four) - Average of last four]

= 4[25 - 20] = 20 .

Borax is prepared from Sodium Carbonate( (Na₂ CO₃) . Borax is a powdery white substance, also known as sodium borate, sodium tetraborate, or disodium tetraborate. It's widely used as a household cleaner and a booster for laundry detergent. It's a combination of boron, sodium, and oxygen.

Na₂ [B₄ O₅ (OH)₄] 8H₂ O

IUPAC ID: Sodium tetraborate decahydrate.

Cinnabar is an ore of mercury.

Cinnabar is a toxic mercury sulfide mineral with a chemical composition of HgS. Cinnabar is a hydrothermal mineral that precipitates from ascending hot waters and vapors as they move through fractured rocks.

• Cinnabar, which is also referred to as mercury sulfide (HgS), is the chief ore mineral of mercury. Commonly, cinnabar is encountered with marcasite, stibnite, and pyrite in veins near recent volcanic rocks and the deposits of hot-springs.
  The essential deposit is at Aimadén - Spain, where it has been mined for over 2,000 years. The other deposits present in Huancavelica, Peru; ludrio - Italy; and the Coast Ranges of California, the U.S. Metacinnabar, which is the isometric (cubic) form of cinnabar, that transforms to cinnabar upon heating at a temperature of 400°- 550° C (750°-1,020° F).
• In general, cinnabar takes place as a vein-filling mineral associated with the alkaline hot springs and recent volcanic activity. This mineral resembles the quartz in symmetry and its exhibiting birefringence. Cinnabar mineral has a mean refractive index around 3.2, a hardness between 2.0 and 2.5, and a particular gravity of 8.1, nearly.
  The properties and colour derive from a structure, which is a hexagonal crystalline lattice that belongs to the trigonal crystal system, crystals that exhibit twinning sometimes.
• Cinnabar mineral has been used for its colour since the antiquity in the Near-East, including as a cosmetic of rogue-type, in China since as early as the Yangshao culture, and in the New World since the Olmec culture, where it was used in colouring stoneware.
• Associated with modern precautions for handling and use of cinnabar arise from the mercury component toxicity, which was recognized as early as ancient Rome.

White Gold is an alloy of gold, nickel and palladium. Utilised for its beauty and corrosion resistance, gold is too soft in its pure form for many practical applications. It is therefore hardened by the addition of other metals, such as copper, silver, nickel, palladium and zinc. This combination of metals is called an alloy.

Hydrogenation of alkenes can be carried out in the presence of nickel.

Hydrogenation is a chemical reaction between molecular hydrogen (H₂) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds.

Chemical oxide reacts with water to produce slaked lime. It is an example of Combination Reaction.

• A Combination reaction is a reaction where two or more elements or compounds combine to form a single compound. e.g. Ca O + H₂O → Ca (OH)₂ + Heat Such reactions are represented by equations of the following form: X + Y → XY.
• A decomposition reaction occurs when one reactant breaks down into two or more products.
• This can be represented by the general equation: AB →A+B.
• The reaction in which oxygen combines with other elements or compounds is known as an oxidation reaction. For example, burning of hydrogen is an oxidation process in which hydrogen combines with oxygen to form water.
• An addition reaction, in organic chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one.

Atomic radius is the measure of the distance between the center of the nucleus to the boundary of the electrons surrounded by it. The Hydrogen atom has an atomic number 1 and a standard atomic weight of 1.008. Its atomic radius is measured to be 53 pm where p m stands for picometer measurement.

Hydrogen has a significant amount of energy due to hydrogen emission spectrum properties. Like all atoms, the presence of electrons can be seen in the hydrogen atom, which is present in its nucleus.

The electric potential between their proton and electron can also be observed, due to which the electron can fulfil quantum values.
We use Neil Bohr’s model to help identify quantum fields in chemistry.

It describes how electrons move around and around the nucleus. Changes in quantum mechanics also showed that electrons do not reside in an orbital rather than an orbital path; they have the same energy level as stated in Bohr’s law.

The hydrogen emission spectrum describes the amount of energy present in hydrogen, in which electrons move from a higher-energy state to a lower-energy state.