Gold has always been a highly prized metal, widely used from the beginning of history as a store of value. It doesn't rust like iron and doesn't become tarnished like silver. It is so chemically inert that it won't react even with the strongest concentrated acids. But it can be dissolved in aqua regia- a fresh-prepared mixture of concentrated {eq}HNO_3 {/eq} and HCl (1:3).

When Germany invaded Denmark in World War II, the Hungarian chemist George de Heresy dissolved the gold Nobel Prizes of Max von Laue and James Franck in aqua ragia to prevent the Nazis from stealing them. He placed the jar with the solution on a shelf in his laboratory, and after the war, precipitated the gold out of the add and returned it to the Royal Swedish Academy of Sciences and the Nobel Foundation who recast the medals and again presented them to Laue and Franck.

The unbalanced equation for the reaction of gold with aqua regia is given below. Add the stoichiometric coefficients to the equation to balance it.

{eq}Au(s)+HNO_3(aq)+HCl(aq) \rightarrow HAuCl_4(aq) + NO_2(g) +H_2O(l) {/eq}

What is the function of HCI?

a. It supplies chloride ions to form a complex ion with the oxidized gold.

b. It acts as an oxidizing agent.

c. It acts as a reducing agent.

The answer to your question really depends on three things: how much water you have, how cold it is to start out, and how cold the things around it are. water actually freezes when it gets to 32 degrees fahrenheit (0 degrees celsius), but the time it takes to get there may be different.  let's start with the first. if you take two glasses, and fill one with a tiny bit of water, and the other about halfway, then put them both in the freezer, the one with less water will freeze first (you can try this at home, but i recommend using plastic cups and not glass ones).  now let's move on to the second part. let's say you have two glasses, and you fill one with really cold water that has been in the refrigerator, and the other with really hot water from the sink. if you put both of them in the freezer, the one that started out colder will freeze first.  for the third part, let's imagine that you have two glasses with the same amount of water in them, and the water is at the same temperature. imagine putting one outside on a really really cold day in georgia, and having a friend in alaska put one outside on the same day. since it would be so much colder in alaska, the glass of water there would freeze before yours.  so, if you took a tiny bit of really cold water in a glass, and put it outside on a cold day in alaska, it would freeze a lot faster than a big glass of hot water outside on a cold day in georgia. 

Ithink the answer is d

2licl + 3o2 i yook the test and it was correct.