General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
21. Propanol belongs to which of the following group?
[C] Carboxylic acid
Correct Answer: A [Alcohol]
Propanol belongs to Alcohol group. Alcohols are suffixed with ‘ol’ and have a functional group OH attached to them. For example: Butanol, Propanol etc.
22. Which of the following is the product of the reaction between Ethanoic acid and Sodium hydrogen carbonate?
[B] Sodium acetate
[D] Sodium hydroxide
Correct Answer: B [Sodium acetate]
Sodium acetate is produced when Ethanoic acid and Sodium hydrogen carbonate reacts with each other. Ethanoic acid reacts with carbonates and hydrogen carbonates to give rise to a salt, carbon dioxide and water.
23. Choose the correct statement about Oxalic acid:
[A] It is weaker than acetic acid
[B] Its condensed chemical formula is HOOCCOOH
[C] Both a and b
Correct Answer: B [Its condensed chemical formula is HOOCCOOH]
Oxalic acid is an organic compound with the formula C2H2O4. Its condensed formula is HOOCCOOH. Its acid strength is much greater than that of acetic acid.
24. Which of the following is produced when wood is burnt in a limited supply of oxygen?
[B] Water gas
Correct Answer: A [Charcoal]
When wood is burnt in a limited supply of oxygen, water and volatile materials present in it get removed and charcoal is left behind as the residue.
25. Which of the following metals can easily be cut with a knife?
Correct Answer: A [Sodium]
Out of all the given options, Sodium is a softer metal and can be easily cut with a knife. It is a highly reactive metal which is silvery white in colour.
26. Which of these non-metals is commonly used as a general anesthetic?
Correct Answer: C [ Xenon ]
Xenon is commonly used in medical science as a general anesthetic. It is a colorless, dense, odorless noble gas found in the Earth’s atmosphere.
27. Which among the following metals is the hardest metal?
Correct Answer: D [Tungsten]
Tungsten has the highest tensile strength of any natural metal, with an ultimate strength of 1510 megapascals. Tungsten has the highest melting point (3422 °C, 6192 °F), lowest vapor pressure (at temperatures above 1650 °C, 3000 °F).
28. When a bond is formed between two atoms, the energy of the system will:
[C] remain the same
[D] may increase or decrease
Correct Answer: C [remain the same]
The fundamental reason for the bonding of atoms is that they lose their stored potential energy by forming bonds. This is the only reason for chemical combination. So, when a bond is formed between two atoms, stored potential energy is always released to the surroundings. However, the total energy of the system involving reaction remains constant.
29. Which of the following is an example of colloidal solution of liquid in solid?
Correct Answer: C [Cheese]
A colloidal solution, occasionally identified as a colloidal suspension, is a mixture in which the substances are regularly suspended in a fluid. Though colloidal systems can occur in any of the three key states of matter gas, liquid or solid, a colloidal solution unambiguously refers to a liquid concoction. Cheese is an example of colloidal solution of liquid in solution.
30. Mass number is always equal to:
[A] number of protons
[B] number of neutrons
[C] sum of number of protons and number of electrons
[D] sum of number of protons and number of neutrons
Correct Answer: D [sum of number of protons and number of neutrons]
Mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom. The mass number is different for each different isotope of a chemical element. This is not the same as the atomic number (Z) which denotes the number of protons in a nucleus, and thus uniquely identifies an element.