name the metals which are soluble only in aqua regia
Aqua regia Aqua regia (/ˈreɪɡiə, ˈriːdʒiə/; from Latin, lit. "royal water" or "king's water") is a mixture of nitric acid and hydrochloric acid,[1] optimally in a molar ratio of 1:3. Aqua regia is a yellow-orange fuming liquid, so named by alchemists because it can dissolve the noble metals gold and platinum, though not all metals.
Seawater Seawater contains more dissolved ions than all types of freshwater.[11] However, the ratios of solutes differ dramatically. For instance, although seawater contains about 2.8 times more bicarbonate than river water based on molarity, the percentage of bicarbonate in seawater as a ratio of all dissolved ions is far lower than in river water. Bicarbonate ions also constitute 48% of river water solutes but only 0.14% of all seawater ions.[11][12] Differences like these are due to the varying residence times of seawater solutes; sodium and chloride have very long residence times, while calcium (vital for carbonate formation) tends to precipitate much more quickly.[12] The most abundant dissolved ions in seawater are sodium, chloride, magnesium, sulfate and calcium.[13] Its osmolarity is about 1000 mOsm/l.[14]