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Question
Water molecule is very polar. Polar end of molecule attracts opposite charges on another water molecule (acts like magnet). How will you explain this property of water with reference to upward movement of water? Comment on the upward movement of water given the intermolecular hydrogen bonding in water.
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Solution
Water molecules are polar. There is a formation of hydrogen bonds between slightly negative and slightly positive charged oxygen and hydrogen bonds respectively when the two water molecules approach each other. The surface tension of the liquid is one of the principal factors of attractive force along with other intermolecular forces. It also helps in dragging water from the xylem to the leaf
Cohesion between water molecules helps in making a continuous column of water in the xylem. This, along with adhesion and surface tension, helps the transpiration pull to pull up the water column in plants. Thus, a multitude of factors is working during the ascent of sap in plants.
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