An exothermic reaction has occurred. You can remember that EXothermic means that energy is EXiting the system. If energy enters the system, it’s endothermic.
The right answer is noble gases.
The noble gases, or rare gases, are the chemical elements of group 18 (formerly "group VIIIA" or even "group 0") of the periodic table. These are helium He, neon 10Ne, argon 18Ar, krypton 36Kr, xenon 54Xe and radon 86Rn, the latter being radioactive.
This property means that they can not bind with other atoms to form molecules or lose electrons to transform into ions, hence their name noble or inert gases (they are not very active and do not do not mix). In nature, all elements "want" to become stable.
The first option. NaOH and H3PO4. This is an hydroxide and one acid. The [OH] from NaOH and the [H] from the H3PO4 will form water, while PO4 and Na combine to form Na3PO4, as per this reaction:
3<span> NaOH + H3PO4
= 3 H2O + Na3PO4</span>
The molarity of a hydrochloric acid solution : 0.32 M
<h3>Further explanation </h3>
Titration is a procedure for determining the concentration of a solution by reacting with another solution which is known to be concentrated (usually a standard solution).
Titrations can be distinguished including acid-base titration, depositional titration, and redox titration. An acid-base titration is the principle of neutralization of acids and bases is used.
Acid-base titration formula
Ma. Va. na = Mb. Vb. nb
Ma, Mb = acid base concentration
Va, Vb = acid base volume
na, nb = acid base valence
1 ⇒HCl (valence=1, HCl ⇒H⁺+Cl⁻, one H⁺)
2⇒Ca(OH)₂(valence=2, Ca(OH)₂⇒Ca²⁺+2OH⁻, two OH⁻)
M₂=0.1 M
V₂=48 ml=0.048 L
V₁=30 ml=0.03 L
An atom becomes an Ion (a) if it gains one or more electron(s) or (b) if it loses one or more electron(s). When it gains electrons it becomes negatively charged and is called an anion. When it loses electron(s) it becomes positively charged and is called a cation
(i looked it up)