Question

Define MCPA.

Answer 1

Hint:MCPA stands for 2-methyl-4-chlorophenoxyacetic acid. MCPA is a herbicide. MCPA is a very powerful, selective and widely used phenoxy herbicide.

Complete answer:
i) 2-methyl-4-chlorophenoxyacetic acid has been extensively used in agriculture in order to control broadleaf weeds.
ii) MCPA is generally a pure brown colour powdered compound.
iii) The mode of action of MCPA is the same as auxin (plant hormones which regulates the growth of the plant).
iv) But the overdose application of the MCPA acts as an herbicide and results in the abnormal growth of the plant.
v) The abnormal growth of the plant can cause stem curl-over, leaf – withering and also plant death.
vi) MCPA is generally absorbed through the leaves (site of the photosynthesis – a process by which plants make their own food with the help of sunlight, water and carbon dioxide) and translocates to the meristems (tissue containing cells which are capable of dividing and never lose their capability of dividing) of the plants.
vii) The carboxylic group of the MCPA allows the formation of the conjugated complexes with metals.
viii) The MCPA residue left in the soil typically has a half – life of 24 days.
ix) The degradation rate of the MCPA in soil also depends upon the environmental conditions such as temperature, moisture and soil.
x) MCPA is also too toxic for aquatic animals.

Note:The molar mass of the MCPA is 200.62 gram per mole (g/mol). Its melting point is 114 degree Celsius to 118 degree celsius. The MCPA is extensively used in the United States of America i.e. USA.