Chemistry Questions and Answers updated daily – General Knowledge

Chemistry Questions: Solved 165 Chemistry Questions and answers section with explanation for various online exam preparation, various interviews, General Knowledge Category online test. Category Questions section with detailed description, explanation will help you to master the topic.

Chemistry Questions

41. The pH value of milk is ___________.




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Correct Ans:6.6
Explanation:
Fresh cows milk has a pH of between 6.7 and 6.5. Values higher than 6.7 denote mastitic milk and values below pH 6.5 denote the presence of colostrum or bacterial deterioration. Because milk is a buffer solution, considerable acid development may occur before the pH changes. That would make it very slightly acidic.
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42. An aqueous solution of copper sulphate is acidic in nature because the salt undergoes ________.




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Correct Ans:hydrolysis
Explanation:
An aqueous solution of copper sulphate is acidic in nature because the salt will undergo hydrolysis.
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43. Which one of the following metals does not form amalgams?




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Correct Ans:copper
Explanation:
The metal copper does not form amalgams.
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44. Which among the following was first human-made plastic?     




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Correct Ans:Celluloid
Explanation:
The first human-made plastic was made by Alexander Parkes in 1855. He created Parkesine, the first man-made plastic.
Parkesine was an organic material derived from cellulose. The new discovery found its use in photographic films.

The first true plastic was made in 1909 by Leo Baekeland, who synthesized Bakelite. The hard plastic could be used to make handles, auto parts, etc.,
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45. Consider the following statements with respect to ‘Bisphenol A’
1. It is used primarily to make plastics.
2. It is used in food packaging items to extend shelf life and protect food from
contamination and spoilage.
Select the correct statements.




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Correct Ans:Both 1 and 2
Explanation:
Bisphenol A is used primarily to make plastics. Bisphenol A based plastics have been in commercial use since 1957. It is a key ingredient in polymers that are used to make adhesives, containers, electronic coatings, boat hulls. In terms of consumer goods, reusable drink containers, food storage containers, canned foods, children's toys, and even receipts from stores.

BPA is used safely in food packaging items to extend shelf life and protect food from contamination and spoilage.
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46. What is the chemical name of Marsh gas?




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Correct Ans:Methane
Explanation:
Methane is called as Marsh Gas. Because it is produced when vegetation decomposes naturally within some geographical marshes, swamps, and bogs.
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47. Which one of the following elements exists in liquid state at room temperature?




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Correct Ans:Mercury
Explanation:
Bromine and mercury are liquid at room temperature and gallium is liquid when just a little above room temperature.

Because of the behavior of the valence electrons, mercury has a low melting point, is a poor electrical and thermal conductor and doesn't form diatomic mercury molecules in the gas phase.
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48. In chemical terms, what are alums used for purifying water for drinking purposes?




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Correct Ans:Double sulphates
Explanation:
Alum is a double sulphate of potash and aluminium.Alum when added to raw water reacts with the bicarbonate alkalinities present in water and forms a gelatinous precipitate. This floc attracts other fine particles and suspended material in raw water, and settles down at the bottom of the container. The water over this sediment is almost clean other than some fine particles dissolved in it.
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49. Galvanization is a process in which metal like iron or steel coated with a thin zinc layer , which serves to protect the metal from ____.




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Correct Ans:Rusting
Explanation:
The process for coating metal like iron or steel with a thin zinc layer is known as galvanization. The zinc layer serves to protect the metal from rusting.
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50. Which gas is responsible for the swelling of bread?




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Correct Ans:Carbon dioxide
Explanation:
Carbon dioxide is one of the major gases responsible for leavening in baking. In cakes, it comes from the reaction of sodium bicarbonate under acidic conditions. In bread making (or special yeasted cakes), the yeast organisms expel carbon dioxide as they feed off of sugars. As the dough rises and proofs, carbon dioxide is formed; this is why the dough volume increases. The carbon dioxide expands and moves as the bread dough warms and bakes in the oven. The bread rises and sets.
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51. The metal compound commonly found in Sindhoor or Kumkum is based on ______.




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Correct Ans:Lead
Explanation:
Sometimes, red lead (lead tetroxide, also known as minium) is added to sindoor. Traditional sindoor was made with turmeric and alum or lime, or from other herbal ingredients.
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52. What is dry ice?




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Correct Ans:Solid Carbon dioxide
Explanation:
Dry ice sometimes referred to as 'cardice', is the solid form of carbon dioxide. It is used primarily as a cooling agent in preserving frozen foods. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere).
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53. Sodium calcium silicate is called _______. 




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Correct Ans:Soft glass
Explanation:
Ordinary glass which is also known as soda glass or soft glass is a mixture of sodium silicate (Na2SiO3), calcium silicate (CaSiO3), and silica (SiO2), and its chemical composition is normally represented as Na2SiO3.CaSiO3.4SiO2 or Na2O.CaO.6SiO2. It is used for making bottles, windows panes, etc.
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54. Which among the following is white phosphorus?




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Correct Ans:P4
Explanation:
White phosphorus is a material made from a common allotrope of the chemical element phosphorus. It exists as molecules made up of four atoms in a tetrahedral structure and is represented by P4. The tetrahedral arrangement results in ring strain and instability. The molecule is described as six single P–P bonds.
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55. Spirit in contact with body gives cool sensation because it is:




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Correct Ans:Highly volatile
Explanation:
Chemical formula for spirit is C2H5OH that it is ethyl alcohol.But spirit is made unfit for drinking by adding Pyridine or methyl alcohol CH3OH or copper sulphate CuSO4. The formula for pyridine is C5H5N. Mineral spirits have a characteristic unpleasant kerosenelike odor. Chemical manufacturers have developed a low odor version of mineral turpentine which contains less of the highly volatile shorter hydrocarbons. Therefore Spirit in contact with body gives cool sensation.
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56. The gas causing acid rain in an industrial area is ___________.




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Correct Ans:Sulphur dioxide
Explanation:
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Scientists have discovered that air pollution from burning of fossil fuels is the major cause of acid rain. The main chemicals in air pollution that create acid rain are sulfur dioxide (SO2) and nitrogen (NOx).
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57. What is the process of conversion from solid to gas is known as?




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Correct Ans:Sublimation
Explanation:
The process of conversion from solid to gas is known as sublimation.

The process of conversion from liquid or gas to solid is known as solidification.

The process of conversion from liquid to gas is known as vaporization.

The process of conversion from gas or vapour to liquid is known as condensation.

Hence, option C is the correct answer.
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58. The metallurgical process in which a metal is obtained in a fused state is called 




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Correct Ans:smelting
Explanation:
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59. The most commonly used bleaching agent is : 




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Correct Ans:chlorine
Explanation:
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60. The nuclear particles which are assumed to hold the nucleons together are




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Correct Ans:mesons
Explanation:
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