All Free Biology MCQs with Answers
Every Biology question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
19844 questions · page 508 of 1985
5071. Benzidineis are:
- A. Analgesic
- B. Antiallergic
- C. Antidepressant
- D. None
Explanation: Benzidineis are antidepressants that can help relieve symptoms of depression, anxiety disorders, social anxiety disorder etc.
Correct answer: Antidepressant5072. In basic dyes which of the following group is present?
- A. -NO2
- B. -SO3OH
- C. -OH
- D. -NH2
Explanation: Basic dyes such as Methylene Blue, Crystal Violet have -NH2 group. These are very powerfull dyes and used to colour wool, silk, cotton etc.
Correct answer: -NH25073. Which is not considered as inorganic antiseptic:
- A. Cl2
- B. I2
- C. SO2
- D. Br2
Explanation: Commonly used inorganic antiseptics are Cl2, I2 and SO2
Correct answer: Br25074. Which of the following is a hypotonic drug?
- A. Luminal
- B. Salol
- C. Catechol
- D. Phenol
Explanation: Salol, catechol and phenol are used as antiseptic. Luminal is used to treat anxiety and sleep disorders so it works as hypotonic drug.
Correct answer: Luminal5075. Which of the following represents liquid propellants?
- A. N2O4 + acrylic rubber
- B. N2O4 + UDMH
- C. Polybutadiene + ammonium perchlorat
- D. Nitroglycerine + nitrocellulose
Explanation: Represents liquid propellants commonly used in rocket engines. This combination consists of nitrogen tetroxide (N2O4) as the oxidizer and unsymmetrical dimethylhydrazine (UDMH) as the fuel. This combination is favored for its storability, high energy density, and relatively low freezing point, making it suitable for long-duration missions and storage in space.
Correct answer: N2O4 + UDMH5076. Malachite green and rosaniline belong to:
- A. Azo dyes
- B. Phthalein dyes
- C. Anthrauinone dyes
- D. Triphenylmethane dyes
Explanation: Malachite green and rosaniline belong to the class of triphenylmethane dyes. Triphenylmethane dyes are characterized by having a central carbon atom bonded to three aromatic rings. Malachite green and rosaniline both have this structural feature.
Correct answer: Triphenylmethane dyes5077. Deepening of colour of compounds may be caused by which of the following:
- A. Bathochromic group
- B. Hypsochromic groups
- C. Chromogens
- D. All the above
Explanation: Deepening of compounds colour is due to bathochromic groups, because in presence of these groups bathochromic shift (Shifting of different spectrum of molecules towards lower frequency) occurs.
Correct answer: Bathochromic group5078. Auxochrome does not deepens the colour of a chromogen if it is present at .................position relative to chromophore.
- A. Para
- B. Meta
- C. Ortho
- D. None
Explanation: Auxochrome does not deepens the colour of a chromogen if it is present at meta position relative to chromophore because meta position is deactivating position for functional groups.
Correct answer: Meta5079. Which one of the following regions of atmosphere contains ozone?
- A. Troposphere
- B. Thermosphere
- C. Mesosphere
- D. Stratosphere
Explanation: Ozone is present in stratosphere and protect us from harmful ultraviolet radiations. Stratosphere is present about 20-25 km above the earth surface.
Correct answer: Stratosphere5080. Minamata disease is due to pollution of:
- A. Organic waste into drinking water
- B. Oil spill in water
- C. Industrial waste mercury into fishing water
- D. Arsenic into the atmosphere
Explanation: Since the discovery of the disease, investigation of the cause has been made, and finally in 1968, the government announced its opinion that Minamata Disease was caused by the consumption of fish and shellfish contaminated by methylmercury compound discharged from a chemical plant. It is neurological syndrome.
Correct answer: Industrial waste mercury into fishing water