Chemistry MCQs

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The primary component for electric vehicle batteries is Lithium, used as Lithium carbonate or Lithium hydroxide. These Lithium-ion batteries have a high power-to-weight ratio, energy efficiency, and thermal stability, leading to their prevalence in electric vehicles. Notably, the boom in EVs has significantly driven the demand for Lithium globally.

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In the human body the most common bio-elements (in decreasing order of occurrence) are oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Other bio-elements include sodium, potassium, magnesium, and copper.

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Caffeine (1, 3, 7-trimethylxanthine) also known as ancient wonder drug is a basically a neurostimulant easily available all over the world and is used in different products like tea, coffee, analgesic adjuvant, soft drinks and many dietary supplements.

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Nitrous oxide is often referred to as “Laughing Gas” due to the euphoric effect it produces when inhaled. Its chemical formula is N2O and it is an oxide of nitrogen. At room temperature, it is a colorless, non-flammable gas with a relatively sweet odor and taste. It is primarily used in dentistry and surgery for its analgesic and anesthetic properties. It is also noted for its role as a major greenhouse gas and air pollutant, as well as a natural regulator of stratospheric ozone.

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The reaction of alkali metals with water produces Hydrogen gas. These metals are part of the first group on the period table and include lithium, sodium, and potassium. They are known for their vigorous reactions with water, which results in the liberation of hydrogen gas. Along with the gas, this reaction also forms a basic alkali metal hydroxide, which gives the solution its characteristic basic or alkaline properties.

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The auto-ignition temperature of a liquid, gas or vapor is the temperature at which the substance will ignite without any external heat source. Here is the temperature of some gases: 
Methane -580 °C 
Hydrogen -560 °C 
Propane -493 °C 
Ethylene -425 °C 
Acetylene -305 °C 
Naphtha -290 °C 
Carbon disulfide -102 °C

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The carbon content of Kerosene is higher than the other fuels mentioned in the option, that is why it will emit maximum mass of carbon dioxide, when the same quantity is burnt.

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Silica is also known as Silicon dioxide, is the most prevalent form of naturally occurring silicon.

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Under ordinary conditions on Earth, elemental hydrogen exists as the diatomic gas, H2. However, hydrogen gas is very rare in the Earth’s atmosphere (1 ppm by volume) because of its light weight, which enables it to escape from Earth’s gravity more easily than heavier gases. However, hydrogen is the third most abundant element on the Earth’s surface, mostly in the form of chemical compounds such as hydrocarbons and water. Hydrogen gas is produced by some bacteria and algae and is a natural component of flatus, as is methane, itself a hydrogen source of increasing importance.

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Plumbism is also known as lead poisoning or  a condition which occurs when there is accumulation of lead in body, usually over a few months' time period and even years.