Chemistry MCQ Questions with Answer for all Competitive Exams

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Chemistry MCQ Questions with Answer


Q31. The purpose of adding sodium sulfate and sodium silicate to the detergent in a washing powder is

1. To keep the washing powder dry
2. To maintain the alkalinity of the powder

Which of these statements is/are correct?

(a) Only 1

(b) Only 2

(c) Both 1 and 2.

(d) Neither 1 nor 2

Answer: (c)

Explanation: The addition of silicates to synthetic detergents has proved very beneficial. Silicates soften water by the formation of precipitates that can be easily rinsed away. Soluble silicates contribute to detergents as cleaning aids, processing aids, and corrosion inhibitors. As for cleaning aids, soluble silicates provide alkalinity and promote soil suspension. Sodium sulfate is simply a filler in detergent powder, in much the same way as fillers are used in many medical tablets, it doesn’t play an active role as such.

Q32. What is the wood spirit?

(a) Methyl Alcohol

(b) Ethyl Alcohol

(c) Butyl Alcohol

(d) Propyl Alcohol

Answer: (a)

Explanation: Methyl Alcohol or Methanol (CH3OH) is known as wood spirit. It is also known as wood alcohol because it was formerly obtained by the destructive distillation of wood.

Q33. Which one of the following metals is less reactive than hydrogen?​​ ​

(a) ​Barium ​

(b)​ Copper ​

(c) ​Lead ​

(d) ​Magnesium

Answer: (b)​

Explanation: ​​In the reactivity series of metals, copper is placed below the hydrogen. Hence, it is less reactive than hydrogen. On the other hand barium, lead and magnesium are placed above the hydrogen hence, these are more reactive than hydrogen.

Q34.Saponification’ is a process by which–

(a) Soap is prepared

(b) Sulphur is extracted

(c) Plastic is prepared

(d) Protein is identified.

Answer: (a)

Explanation: Saponification is the alkaline hydrolysis of the fatty acid esters. Example: The chemical reaction between fatty acid and sodium hydroxide is a saponification reaction.

Triglyceride + Sodium hydroxide → Glycerol + 3 soap molecules.

Q35. ​C11 – L – methyl-methionine is used for

​(a) ​Brain tumor and parathyroid imaging ​

(b)​ Stomach analysis ​

(c)​ Bone imaging ​

(d)​ Live imaging

Answer: ​(a)​

Explanation: C11-L-methyl-methionine is used in position emission tomography (PET) to locate and differentiate primary brain tumors and also to monitor the therapeutic effect of tumor irradiation.

Q36. Consider the following statements:

1. Liquefied natural gas (LNG) is liquefied under extremely cold temperatures and high pressure to facilitate storage or transportation in specially designed vessels.
2. The first LNG terminal in India was built in Hassan.
3. Natural gas liquids (NGL) are separated from LPG and these include ethane, propane, butane and natural gasoline.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 3

(c) 2 and 3

(d) 1, 2, and 3

Answer: (b)

Explanation: Liquefied Natural Gas or LNG is natural gas (predominantly methane, CH4) that has been converted temporarily to liquid form for ease of storage or transport. The liquefaction process involves the removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream. The natural gas is then condensed into a liquid maximum transport pressure set at around 25 kPa/3.6 psi by cooling it to approximately –162 °C (–260 °F). Dahej, in India, has begun its first import of natural gas.

Natural gas liquids recovery (NGL) involves refrigerated gas plants, turboexpanders, and debutanizers, depropanizers, and JT plants. NGL can be separated using debutanizers and depropanizers into propane, butane, naphtha, etc.

Q37. The toxic gas present in the smoke exhausted by cars is–

(a) CO

(b) CO2

(c) C2H4

(d) CH4

Answer: (a)

Explanation: Car and other automobiles exhaust mainly contains CO, lead and SO2 and out of these CO is the most toxic.

Q38. Which one of the following is another name of RDX?

(a) Cyanohydrin

(b) Dextran

(c) Cyclohexane

(d) Cyclonite

Answer: (d)

Explanation: RDX, an initialism for Research Department Explosive, is an explosive nitroamine widely used in military and industrial applications. It is also known less commonly as cyclonite. Its chemical name is cyclotrimethylene trimipramine.

Q39. Who coined the Chipko slogan “Ecology is Permanent Economy“?

(a) Chan Prasad Bhatt

(b) Sundarlal Bahuguna

(c) Shyam Prasad Bahuguna

(d) Bachni Devi

Answer: (b)

Explanation: Sundarlal Bahuguna coined the Chipko slogan “Ecology is Permanent Economy”. The first chipko action took place spontaneously in April 1973 in the village of Mandal in the Upper Alaknanda Valley and over the next five years spread to many districts of the Himalayas in Uttarakhand.

Q40. Alum stops bleeding in a minor cut because of–

(a) Salvation

(b) Emulsion

(c) Dialysis

(d) Coagulation

Answer: (d)

Explanation: Alum stops bleeding in a minor cut. Its chemical name is potassium aluminum sulfate. It stops bleeding because of coagulation. Blood is a colloid of proteins in water and the K+, Al3+, and SO4 ions coagulate them, causing a blood clot.

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