Free Practice Questions for Chemistry in General-studies

Cobalt belongs to Group 9 of the periodic table.

Important Points:

Cobalt -

• It is located in period 4 and block d of the periodic table.
• Cobalt  belongs to transition metal.
• Melting Point - 1495 °C 
• Boiling Point - 2927 °C  
• Atomic Number - 27 
• Symbol - Co 

Periodic Table -

• The periodic table has 18 vertical columns called 'groups' and 7 horizontal rows called 'periods' .
• All the elements in the periodic table are arranged according to their chemical properties.

Acid drain cleaners typically contain a high concentration of sulphuric acid(H₂SO₄) or hydrochloric acid (HCL), and usually come in liquid form.

Important Points:

• They work by a process of acid hydrolysis to dissolve the fats and solids that create a drain blockage.
• Acid hydrolysis is the process of breaking down large dilutions of acid and water in any substance.
• Acids 'loan' their hydrogen atoms to water molecules to produce a chemical reaction.
• Acid drain cleaners are poured into the drain and allowed to sit for several minutes while they work.
• There are four types of chemical drain cleaners; Acid, caustic, oxidizing and enzymatic. 

Beryllium has  the property of forming covalent compounds.

Important points:

• Beryllium is a relatively soft silvery-white metal with a low density.
• Beryllium is a chemical element with the symbol (Be) and atomic number (4).
• Beryllium has the highest melting point. It is useful in nuclear work as well as in ceramic application.
• Beryllium is used to make gears and cogs, particularly in the aviation industry.
• Beryllium is used as an alloying agent in the production of beryllium copper.
• Beryllium is an alkali earth metal and steel-gray, strong, light, and brittle.
• Beryllium is one of the most toxic elements in the periodic table.
• It is a metal that can be very harmful if inhaled by humans as it can damage the lungs and cause pneumonia.

Red cabbage contains a chemical called anthocyanin that turns pink/red in the presence of acid, turns purple when neutral, and blue/green when mixed with alkaline substances.

Important Points:

• A dye that changes colour when inserted in an acid or base is called an indicator.
• Red cabbage contains a signaling pigment molecule called flavin, which is a variant of the molecule called anthocyanin.
• Red cabbage that is mostly found in homes can be used to prepare a solution that acts as a pH indicator.

When an acid or a base is mixed with water, Decrease in the concentration of ions (H3O+/OH-) per unit volume .

Important points:

• Dilution is the process of adding a solvent, which lowers the concentration of a solute in a solution.
• Dilute acids have a low concentration of acids in aqueous solutions.
• Concentrated acids have a high concentration of acids in aqueous solutions.
• A solute is a substance that is added to a solvent to form a solution.
• Solvent is a substance that dissolves solute particles during the formation of a solution.

Muriatic acid is another name for hydrochloric acid. Its chemical formula is HCl.

Important Points:

• Hydrogen chloride is obtained by heating sodium chloride and concentrated sulfuric acid.

                                                     NaCl  +  H₂SO₄ → NaHSO₄  + HCl

• Hydrochloric acid is an inorganic chemical.
• Its aqueous solution is acidic.

 Option Explanation:

Lithium metal which has atomic number 3 is a soft, silvery metal with very low density, reacts vigorously with water and corrodes quickly in air.

Important Points:

• Lithium is used to make high-temperature lubricating greases in glass and ceramics. 

• Lithium and sodium metals are soft and can be cut with a knife. 

• The density of lithium is very low.

• It has the highest specific heat capacity of a solid element.

Cyanide ion - CN^- is the correct .

Important points:

Cyanide ion

• Cyanide has one carbon atom and one nitrogen atom linked to each other by a triple bond.
• Its molar mass/molecular weight is 26.02 g mol⁻¹ .
• It  is also known as nitrile ion and cyanide ion.
• Bacteria such as fungi ,algae and bacteria can produce cyanide.
• It is used in making jewellery.
• Sodium cyanide is very toxic  .

Wood, air and sand are mixtures and water is a compound.

Important Points:

Mixture  -

• A mixture is an impure substance that contains more than one type of particle.
• The components can be separated quite easily by physical methods.
• It does not have a definite melting point and boiling point.
• Example-  air, sand, sea water, gunpowder, wood etc.

Compound-

• A compound is a substance made of two or more different types of elements, chemically combined in a definite proportion.
• The properties of a compound are different from those of its constituent elements.

All are correctly matched.

Important Points:

• The components of a colloidal solution are the dispersed phase and the dispersion medium. 

Given:-

Moles of N₂ gas = 2 mole

Molar mass of N₂ = 28 g/mole

Moles = mass of N₂ /molar mass of N₂

2 = mass of N₂ / 28

Mass of N₂ = 28 X 2 

                   = 56 g

Ethylene glycol is used as an anti-freezing substance in the self starting engines.

Important Points:

• Ethylene glycol is used as an ingredient in printing inks, and paint solvents.
• Ethylene glycol is highly toxic to humans therefore, it is not used in foodstuffs.

Option Explanation:

The quality of diesel is expressed by Cetane number.

Important Points:

• The quality of petrol is expressed by Octane number.
• Diesel is obtained from the refining of petroleum. 
• Petroleum:  also known as Black gold and traditional oil or light oil.

The king of chemicals is known as Sulphuric acid(H2SO4).

Important Points:

• It is a strong mineral acid. It is manufactured by contact process.
• It was the 1st mineral acid that was discovered in laboratory. 
• It is strong oxidizing agent and good dehydrating agent.

Option Explanation:

Lead oxide is also known as white lead is a incorrect statement, because lead carbonate is known as white lead. 

Important Points:

Lead -

• Atomic number - 82
• It is used in making alloys, lead accumulators.
• It is used in covering of electric cables.
• It is used in lead chambers, lead pipes and in nuclear reactors.
• Lead oxide is amphoteric oxide. It is used in rubber industry and storage batteries.
• Pb₃O₄is called red lead. it is used in making red paint, flint glass, etc.

Phenolphthalein is a synthetic indicator. Litmus, Turmeric, and Red cabbage are the natural indicators of acids and bases.

Important Points : 

Natural indicators:-

• Indicators found in nature, mostly derived from plants, to test whether a substance is acidic or basic, are called natural indicators.

Carbon dioxide gas is produced when Eno salt is dissolved in water. 

Important Points:

• ENO is a mixture of Citric acid, Sodium bicarbonate, and Sodium Carbonate.
• It is an antacid, which produces gas bubbles and sodium bicarbonate helps in neutralization of stomach acid to relieve the pain.
• Solid carbon dioxide is called dry ice.
• CO₂ is an important greenhouse gas.
• An increase in CO₂ concentrations in our atmosphere is causing average global temperatures to rise, disrupting other aspects of earth's climate.

Potassium carbonate is known as pearl ash.

Important Points :

• Potassium carbonate is used in the manufacture of soaps, detergents and glass, and to remove the hardness of hard water.
• Potassium nitrate is used in the manufacture of gunpowder.
• Potassium permanganate is used to purify drinking water.
• Sodium chloride is used in the production of sodium hydroxide, sodium carbonate, baking soda, etc., and for de-icing of roads.

Zinc chloride, ZnCl₂ prevents wood furniture from termites. 

Important Points:

• It is used as a disinfecting agent, condensing agent, and dehydrating agent. 
• Zinc phosphide, (Zn₃P₂₎ is used as a rodenticide.
• Hydrated zinc sulphate is also known as white vitriol. Its chemical formula is ZnSO₄.7H₂O. It is used in the preparation of lithopone(ZnS + BaSO₄).
• Zinc oxide, is also known as philosopher’s wool. It is an amphoteric oxide.

Wilson is a diseases caused due to excess of amount of copper.

Important Points:

• Wilson disease is an inherited disorder in which excessive amounts of copper accumulate in the body, particularly in the brain ,liver and and and eyes. 
• Copper carries by bile, along with other toxins and waste products, out of the body through the digestive tract. 
• In Wilson disease, the liver releases less copper into bile, and extra copper stays in the body.
• Bile helps into digestion ,it breaks down fat into fatty acid which can taken into the body by the digestive tract.