no liquid ionic compound are known ,but many of of the known covalent compounds are liquids and some are gases. account for these differences

Explanation:

No liquid ionic compounds are known but many of the unknown covalent compound are liquid, and some are gases. ... Although it is true that many ionic compounds have melting points above room temperature, not all do. Ionic liquids do exist at room temperature. A good example is the trihydrate of zinc chloride.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.