Which one of the following is NOT an example of organic compound?
- A.Ammonium cyanate
- B.Marsh gas
- C.Urea
- D.Cane sugar
Correct answer
Explanation
The correct answer is A, Ammonium cyanate. It is an inorganic salt made of the ammonium ion and the cyanate ion, with no carbon–hydrogen bonds.
Ammonium cyanate is famous in chemistry because in 1828 Friedrich Wöhler heated it and obtained urea. This was the first organic compound made in a laboratory from an inorganic substance, and it weakened the old "vital force" idea that organic compounds could be made only by living things. Compounds such as carbonates, cyanides and cyanates are classed as inorganic even though they contain carbon.
B is wrong because marsh gas is methane, CH₄, the simplest organic compound, given off by rotting plant matter in marshes.
C is wrong because urea, CO(NH₂)₂, is the organic compound Wöhler made and is found in urine.
D is wrong because cane sugar is sucrose, C₁₂H₂₂O₁₁, an organic carbohydrate.
Exam tip: Wöhler, 1828: ammonium cyanate (inorganic) on heating gives urea (organic).
Practice Questions
View allMarginal placentation, in which the ovules are borne along the fused margin of a single carpel, is found in
- A.Tomato
- B.Pea
- C.Mustard
- D.Sunflower
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The pea's ovary is made of one carpel whose two margins fuse to form a ridge, and the ovules are arranged in two rows along that ridge; this is marginal placentation, and it is why the pod opens to show a single row of seeds on each side.
Read the full explanation →Mango and coconut are examples of which type of fruit?
- A.Berry
- B.Drupe
- C.Pome
- D.Legume
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A drupe is a fleshy fruit with a thin epicarp, a mesocarp that may be pulpy as in the mango or fibrous as in the coconut, and a hard, stony endocarp enclosing a single seed; the coconut's shell is that endocarp and the white kernel is the seed.
Read the full explanation →The apple is regarded as a false fruit because
- A.It has no seeds
- B.It develops from the thalamus along with the ovary
- C.It develops without fertilisation
- D.Its pericarp is stony
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A true fruit forms from the ovary alone, but in the apple and the pear the thalamus grows, becomes fleshy and forms the greater part of the edible tissue, while the ovary makes only the core; such a fruit is called a false or spurious fruit, and the specific type…
Read the full explanation →Vexillary aestivation of the corolla is found in the flower of
- A.Pea
- B.Cotton
- C.Calotropis
- D.Gulmohar
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In vexillary or papilionaceous aestivation the corolla has five petals of unequal size: one large posterior petal, the standard, which covers two lateral wing petals, which in turn cover the two smallest anterior petals that are fused into a keel.
Read the full explanation →In a racemose inflorescence, the flowers are borne in
- A.Basipetal succession
- B.Acropetal succession
- C.A single terminal cluster
- D.No definite order
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In a racemose inflorescence the main axis does not end in a flower but keeps growing, so the lowest flower is the oldest and the youngest buds are at the tip; this upward order is called acropetal, as in radish, mustard and Larkspur.
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