a lunar eclipse occurs on a full moon day while a solar eclipse occurs on a new moon day.why?

it is simple enough lunar eclipse occurs when earth comes in between the sun and the moon and blocks the sun rays to reach the moon and thus we cannot see the moon. Now it does not matter if there is a full moon or not. Full moon is when moon is reflectiing all of the sun's light in one of the days of its 28 days revolution around the earth. But in lunar eclipse the sun, the earth and the moon have to be in line. this is not the case in a full moon always, but may happen anytime considering the revolution period of earth around the sun and moon around the earth. So a full moon does not have to result in a lunar eclipse. They are two different phenomenas.

-----------------The moon's orbit around the Earth is inclined about 5 deg to the Earth's orbit around the sun. Since the moon only appears half a degree wide, you can understand that most of the time that 5 deg mismatch causes the moon to not align perfectly every time.Depending on the date, the full moon can be anything up to 5 deg too high or 5 deg too low to completely line up.