General Knowledge Mock Test - 8 - CDS MCQ

The process of converting a solid directly into a gas is called (b) Sublimation. Sublimation occurs when a solid undergoes a phase change and directly transitions into a gaseous state without passing through the liquid phase.

The modern periodic table contains seven periods, or horizontal rows of elements.

Acid: The compound that produces hydrogen ion when it dissolved in the solution is called acid.

• The acidic property depends on the concentration of the Hydrogen ion in the solution.

• H+ ion cannot exist alone. It always conjugates with the water and forms hydronium ion(H3O+)

The identification of the acidic or basic nature of any salt solution by the reactions:

• Strong acid + strong base → water + neutral salt
• Weak acid + strong base → water + basic salt
• Strong acid + weak base → water + acidic salt
• Weak acid + weak base → water + salt (It may be a neutral, acidic, or basic depending on the reactants used in the reaction)

EXPLANATION:

• KNO₃ is completely ionized in the water that gives the Nitric acid which is a strong acid. So KNO3 can be used for identifying an acid solution. Hence option 2 is correct.
• The K⁺ is an unreactive ion because it is produced from the dissolution of the strong base (KOH). So K2SO4 can't be used to identify the acidic solution.
• NaCl is a neutral solution that's why we can't use it also.
• Since Na2CO3 is formed by a weak acid Carbonic acid (H2CO3). That's why it can't be used also.

Copper is a metal and metals do not form covalent bonds. They form metallic bonds which involve the sharing of free electrons among a lattice of positively charged ions. On the other hand, Ice, Diamond, and Graphite are all made up of non-metals, and non-metals form covalent bonds by sharing electrons. Therefore, the solid that does not contain a covalent bond is Copper.

According to Goldstein's experiment, which was conducted in the late 19th century, the discovery made was actually related to the existence of positively charged particles in a gas discharge tube. Wilhelm Wien later named these particles "protons."

Rusting of iron is an example of oxidation as iron loses electrons to form iron oxide (rust).

Silver is the best conductor of electricity among common metals. It has the highest electrical conductivity and thermal conductivity, which makes it valuable in electrical and electronic applications.

According to Newton's law of universal gravitation, the force of gravitational attraction between two objects is inversely proportional to the square of the distance between their centers. Mathematically, it can be represented as:

F = G * (m1 * m2) / r²

Where:

• F represents the force of gravity between the two masses,
• G is the gravitational constant,
• m1 and m2 are the magnitudes of the masses of the objects, and
• r is the distance between the centers of the objects.

So, as the distance between the masses increases, the gravitational force between them decreases, following the inverse square relationship.

The pressure exerted by a fluid is affected by factors such as the density of the fluid, the depth of the fluid, and the acceleration due to gravity. Temperature does not directly affect the pressure exerted by a fluid.

The phenomenon that explains why sound is heard at longer distances at night than during the day is due to refraction. At night, the air above the ground is warmer, causing the sound waves to bend towards the earth. This is known as a temperature inversion. Therefore, the correct answer is:

D: Refraction

Herbivore is a primary consumer in an ecosystem. Herbivores are organisms that feed exclusively on plants. They obtain their energy by consuming plant material, making them the first level of consumers in a food chain or food web.

Carbon dioxide is a greenhouse gas. Greenhouse gases are those that trap heat in the Earth's atmosphere, contributing to the greenhouse effect and global warming. Other greenhouse gases include methane, nitrous oxide, and water vapor. Carbon dioxide is primarily released through human activities such as burning fossil fuels, deforestation, and industrial processes.

Endocrine glands are ductless and release hormones directly into the bloodstream, affecting distant target cells. Exocrine glands, on the other hand, release their secretions through ducts to the body's surface or into body cavities, such as sweat, saliva, or digestive enzymes. This key difference distinguishes the functions of endocrine and exocrine glands in the body.

Thomas Edison is credited with inventing the practical incandescent light bulb. Although there were previous inventors who developed early versions of electric lighting, Edison's design was the first commercially successful and long-lasting light bulb. He patented his invention in 1879.

The instrument used to measure the intensity of earthquakes is (c) seismograph. A seismograph is a device that detects and records the vibrations caused by seismic waves, which are generated by earthquakes. It measures the intensity and duration of ground motion during an earthquake, providing valuable data for earthquake studies and monitoring.

Boyle's law states that at constant temperature, the pressure and volume of a gas are inversely proportional.

Ethane is an example of a saturated hydrocarbon. Saturated hydrocarbons contain only single covalent bonds between carbon atoms and are fully saturated with hydrogen atoms.

The octet rule states that atoms tend to combine in such a way that they each have eight electrons in their valence shells, giving them the same electronic configuration as a noble gas.

Phosphorus (P) is an exception to the octet rule. It can expand its valence shell to hold more than eight electrons. This is possible because phosphorus (as well as sulfur and chlorine) has empty d orbitals in the third energy level that can accept extra electrons. Therefore, phosphorus can form compounds where it is surrounded by more than eight electrons, such as PCl5 (Phosphorus pentachloride), which does not follow the octet rule. So, the correct answer is D. P (Phosphorus).

Carbon emissions are the main cause of the greenhouse effect. When carbon dioxide and other greenhouse gases are released into the atmosphere through human activities, such as burning fossil fuels and deforestation, they trap heat from the sun, leading to a rise in global temperatures. This phenomenon is known as the greenhouse effect and is a significant driver of climate change.

Species diversity is the term used to describe the variety of different species in an ecosystem. It takes into account both the number of species present (species richness) and the relative abundance of each species (species evenness). Species diversity is an important indicator of the health and stability of an ecosystem.

The average blood volume for an adult is about 5 liters. This value can vary depending on factors such as body size, age, sex, and overall health. However, 5 liters is a commonly accepted estimate for the average blood volume in an adult human.

H1N1 virus, also known as the influenza A (H1N1) virus, is mentioned in the news with reference to Swine Flu. Swine flu is a respiratory disease caused by the H1N1 influenza virus, which can infect pigs and occasionally spread to humans, leading to flu-like symptoms.

Article 15 of the Indian Constitution guarantees the Right to Equality, which prohibits discrimination on the grounds of religion, race, caste, sex, or place of birth.

• The Union executive of the government of India consists of the President, the Vice- President, the Prime Minister, the council of ministers and the attorney general of India.
• Chief Justice of India does not form a part of the Union executive.
• The Union executive consists of the President, the Vice-President, and the Council of Ministers with the Prime Minister as the head to aid and advise the President.
• The Chief Justice of India is the Head and Chief Judge of the Supreme Court, which consists of a maximum of 34 judges.
• The Constitution requires the president to submit nominations to the Senate for its advice and consent.

The concept of Gram Sabha is derived from the ancient Indian tradition mentioned in the Rigveda, where the village assembly played a crucial role in decision-making.