Free Practice Questions for Chemistry in General-studies

The chemical name of the gammaxene compound is benzene hexachloride.

Important Points:

• Its chemical formula is C₆H₆Cl₆.
• It is an organochlorine compound. It is used to treat lice and scabies.
• It is a strong insecticide. It is generated when chlorine is added to benzene in presence of sunlight.
• It is one of the stereoisomers of hexachlorocyclohexane.

The gas present in an electric bulb is Argon.

Important points:

• Argon is an inert gas, which means that it does not react with other substances.
• This makes it ideal for use in electric bulbs, as it prevents the tungsten filament from oxidizing and burning out prematurely.
• Other gases that are sometimes used in electric bulbs include nitrogen, neon, and krypton.
• The choice of gas depends on the desired properties of the bulb, such as its color and lifespan.

Smelite is an ore of cobalt.

 Important points:

• Smelite is a cobalt arsenide mineral with the chemical formula CoAs2.
• It is a dark gray to black mineral with a metallic luster.
• Smelite is found in hydrothermal veins and is often associated with other cobalt ores, such as cobaltite and skutterudite.
• Smelite is an important source of cobalt, which is used in a variety of applications, including magnets, batteries, and catalysts.

Triiodomethane is also known as iodoform. It was used earlier as an antiseptic.

Important Points:

• The antiseptic properties are due to the liberation of free iodine and not to iodoform itself.
• Its chemical formula is CHI₃.

Option Explanation:

Argon gas is used to provide inert atmosphere.

Important Points:

• Group 18 elements, often known as noble gases, are made up of six elements: helium, neon, argon, krypton, xenon, and radon. All of these are gases that are chemically inert. 
• Argon is mostly utilised in high temperature metallurgical processes (arc welding of metals or alloys) and to fill electric bulbs.
• Helium is used to fill balloons for meteorological observations. 
• Neon is used in discharge tubes and fluorescent lamps to display advertisements. 
• Radon is a naturally occurring radioactive element. It is used in cancer radiation.
• Xenon is also known as stranger gas. It can be found in flash lamps.

Silver sulphide, is black in colour. 

Important Points:

• Silver reacts with hydrogen sulphide gas in the air and forms a thin black layer of silver sulphide on it.
• It is used as a photosensitizer in photography.
• Silver sulphide is insoluble in most solvent ,but it is degraded by strong acid.

Bromine  is not a noble metal.

Important Points:

• A class of metals known as noble metals are resistant to oxidation and corrosion when exposed to air.
• Gold (Au), Silver (Ag), Platinum (Pt), Rhodium (Rh), Iridium (Ir), Ruthenium (Ru), Osmium (Os), and Palladium are examples of noble metals (Pd).
• The transition metals group includes the noble metals, which are found in the center of a table.

Sulphur is used in the vulcanization of rubber.

Important Points:

• To improve the physical properties of the natural rubber, a process of vulcanization is carried out. 
• This process consists of heating a mixture of raw rubber with Sulphur and an appropriate additive at a temperature range between 373 K to 415 K.
• On vulcanization, Sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.
• In the manufacture of tyre rubber, 5% of Sulphur is used as a crosslinking agent.

Marshall’s acid is the common name of H2S2O8.

Important Points:

• Marshall’s acid got its name from the chemist Hugh Marshall. 
• It is also known as peroxydisulfuric acid. 
• It is an inorganic compound containing two sulphate groups and one peroxide group.

Urea was the first organic compound synthesized in a laboratory.

Important Points:

• Urea, also known as carbamide, is an organic compound with the chemical formula NH2CONH2.
• It is a nitrogenous organic compound. It is used as a fertilizer, in the manufacture of melamine – urea resin.

Option Explanation:

 Chlorine is used for the preparation of PVC plastic.

Important points:

• PVC plastic is made from vinyl chloride, which is a compound of chlorine and hydrogen.
• The chlorine atoms in vinyl chloride give PVC its strength and durability.
• Other chemicals, such as stabilizers and plasticizers, are also added to PVC to improve its properties.

Glutamic acid is present in wheat.

Important Points:

• An acid is a substance that furnishes hydrogen ions (H⁺) when dissolved in water. 
• Some examples of acids are- Hydrochloric acid (HCl) in gastric juice, Ascorbic acid (vitamin C) in lemon , Malic acid in apples, Benzoic acid in grass, Tannic acid in tea, Nitric acid (HNO3) used in laboratories, Glutamic acid in wheat.

'Zinc' is the correct answer.

Important Points:

• A transition element is defined as one which has incompletely filled d orbitals in its ground state or in any one of its oxidation states. 
• Zinc, cadmium and mercury of group 12 have full d¹⁰ configuration in their ground state as well as in their common oxidation states and hence, are not regarded as transition metals.

Zinc(Zn)-

• Atomic number -30
• It is a d-block element.
• Ores of zinc- Zinc blende or Sphalerite ZnS, Calamine ZnCO₃, Zincite ZnO
• Zinc is used for galvanising iron. 
• It is also used in large quantities in batteries, as a constituent of many alloys, e.g., brass, (Cu 60%, Zn 40%) and German silver (Cu 25-30%, Zn 25-30%, Ni 40–50%). 
• Zinc dust is used as a reducing agent in the manufacture of dye stuffs, paints, etc.

Lithium is the lightest metallic element. It is a strong reducing agent.

Important Points- 

• Lithium metal is used to make useful alloys, for example with lead to make 'white metal' bearings for motor engines, and with aluminum to make aircraft parts. 
• It is used in thermonuclear reactions.
• Lithium is also used to make electrochemical cells.

Option Explanation

• Osmium is the heaviest element.
• Gold, platinum, silver and mercury are called noble metals.
• Mercury is the only metal and bromine is the only nonmetal that is liquid  at room temperature.
• Gold, silver and platinum are found in free state. This is due to their low reactivity as compared to other metals.
• Graphite is the only non-metal which is a good conductor of electricity.
• The melting points of gallium and cesium  are very low. It melts when you put them on your palm.

• Acidic and alkaline solutions formed in water conduct electricity because they generate hydrogen and hydroxide ions respectively.

Additional Information-:

• Acids and bases show their conducting properties only when they are in aqueous solution because they can completely ionize in water.
• According to Arrhenius' concept, acids are those which, when dissolved in water, produce hydrogen ions (H⁺).
• When dissolved in water, bases produce hydroxide ions (OH^-).
• These ions, when in water, act as charge carriers and can therefore conduct electricity.
• The pH level is a measure of the number of hydrogen ions in a solution.
• The lower the solution or compound on the pH scale, the higher the concentration of hydrogen ions.

Iodine solution test is used to detect the presence of starch.

Important Points:

Iodine solution -

• The iodine test is a characteristic test for starch only. 
• The iodine test can also help to distinguish starch from monosaccharides, disaccharides, and other polysaccharides. 
• The appearance of blue-black color indicates the presence of the starch in the sample.

Molisch’s test is used to detect the presence of carbohydrates.

IMPORTANT FACTS

Molisch's reagent-

• This is a general test for all carbohydrates. 
• The formation of the purple colored ring at the interface between the sulphuric acid and the test solution shows the positive result.
• The absence of color indicates a negative result.
• It can be used to differentiate proteins and amino acids from carbohydrates.  

ADDITIONAL INFORMATION

• Iodine solution -The iodine test is a characteristic test for starch only. 
• Fehling's test is used to determine if a reducing sugar is present in a sample using a reagent called the Fehling's reagent.

Fats are made up of glycerol and fatty acids.

IMPORTANT FACTS

Fats

• Fats are important for good health and proper functioning of the body.
• Fats are triglycerides made up of a combination of different building blocks; glycerol and fatty acids.
• Fats are the backup source of energy when carbohydrates, which are the main source of energy are unavailable.
• Fats are necessary for the synthesis of steroid hormones such as estrogen, progesterone, and testosterone which are important for the reproductive function

ADDITIONAL INFORMATION

Types of fats-

Saturated fat :

• Saturated fats contain no double bonds in their chemical structure.
• They are solid or waxy at room temperature.

Unsaturated fat-

• Unsaturated fats are liquid at room temperature. 
• They contain one or more double bonds

Leucine is an example of essential amino acid.

IMPORTANT FACTS

Essential amino acids :

• Nine of the twenty amino acids are categorized as essential, which include leucine, isoleucine, valine, lysine, methionine, phenylalanine, threonine, histidine and tryptophan.
• Tryptophan is used to make niacin, melatonin, and serotonin, which promote healthy sleep and a positive mood state.
• Leucine helps stimulate muscle protein synthesis

ADDITIONAL INFORMATION

Non-Essential amino acids :

• Non-essential amino acids are those that your body naturally produces and therefore not essential to acquire through dietary sources.
• Alanine, asparagine, aspartic acid, glutamic acid, arginine, cysteine, glutamine, glycine, proline, serine, tyrosine are all considered nonessential amino acids

Biuret test is used to detect the presence of peptide bond.

IMPORTANT FACTS -

Biuret test :

• The biuret reagent is pale blue when pure.
• A positive test is indicated by a deep blue/purple color due to the copper ion complex with the amide group of the protein.
• All proteins and peptides give positive results.

OPTIONS EXPLANATION

• Ninhydrin test is used to indicate the presence of α-amino acids in proteins.
• Fehling's test is used to determine if a reducing sugar is present in a sample using a reagent called the Fehling's reagent.