Effect of molecular weight
At constant pressure and temperature, the root-mean-square speed and therefore the effusion rate are inversely proportional to the square root of the molecular weight. Gases with a lower molecular weight effuse more rapidly than gases with a higher molecular weight, so that the number of lighter molecules passing through the hole per unit time is greater. Grahams law
Scottish chemist Thomas Graham (1805–1869) found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles. In other words, the ratio of the rates of effusion of two gases at the same temperature and pressure is given by the inverse ratio of the square roots of the masses of the gas particles.
Terazosin, sold under the brand name Hytrin among others, is a medication used to treat symptoms of an enlarged prostate and high blood pressure. For high blood pressure, it is a less preferred option. It is taken by mouth.Common side effects include dizziness, headache, tiredness, swelling, nausea, and low blood pressure with standing. Severe side effects may include priapism and low blood pressure. Prostate cancer should be ruled out before starting treatment. It is an alpha-1 blocker and works by relaxing blood vessels and the opening of the bladder.Terazosin was patented in 1975 and came into medical use in 1985. It is available as a generic medication. In 2019, it was the 203rd most commonly prescribed medication in the United States, with more than 2 million prescriptions. Synthesis

Reaction of piperazine with 2-furoyl chloride followed by catalytic hydrogenation of the furan ring leads to 2. This, when heated in the presence of 2-chloro-6,7-dimethoxyquinazolin-4-amine (1) undergoes direct alkylation to terazosin (3). == References ==