What is aqua regia solution ?​

Explanation:

Aqua regia is a mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3.

Explanation:

Aqua regia is a corrosive, fuming yellow solution that is a 1:3 mixture of concentrated nitric and hydrochloric acids. It is commonly used to remove noble metals such as gold, platinum and palladium from substrates, particularly in microfabrications and microelectronics labs.

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.