This problem has two parts; the first one asking for the concentration of NaBr given both its mass and volume and the second one asking for its volume given both mass and concentration. The answers turn out to be 0.158 M and 211 mL.
<h3>Molarity</h3>
In chemistry, the use of units of concentration depends on both the substances to analyze and their amounts. In such a way, for molarity, one needs the following relationship between the moles of solute and volume of solution:

Thus, for the first part of the problem we first calculate the moles in 2.60 g of NaBr via its molar mass:

Next, we convert the 160. mL to L by dividing by 1000 in order to obtain 0.160 L to subsequently calculate the molarity:

Next, since the moles remain the same and for the second part we are asked for the volume given the concentration, one can solve for the volume so as to obtain:

That in milliliters turns out to be:

Learn more about molarity: brainly.com/question/10053901
The chemical formula : X₃Y₂
<h3>Further explanation </h3>
The noble gas element is a stable class of elements. The noble gas element is monatomic. Stability of noble gases is caused by an electron configuration that has a stable configuration of 8 (has 8 valence electrons) except He with a duplet configuration (has 2 valence electrons)
Other elements that do not yet have electron configurations such as noble gases will try to achieve their stability by forming bonds between elements.
This is generally called the octet rule
X has 2 valence electrons.to achieve stability, element X will release 2 electrons to form X²⁺
Y has 5 valence electrons, to achieve stability, the element Y will attract/ add electrons to form Y³⁻
The two compounds will form a compound with the charges crossed : X₃Y₂
Pros
It doesn't cost much
Power stations are ver compact
Transportation of the material is easy
Cons
It isn't safe
Nuclear waste take 200 years to degrade
Greater risk of explosion.