Potassium or any other metals.
Answer:
0.12 M
Explanation:
Step 1: Write the balanced equation
NaOH + HCl ⇒ NaCl + H₂O
Step 2: Calculate the reacting moles of NaOH
10 mL of a 0.30 M NaOH solution react.

Step 3: Calculate the reacting moles of HCl
The molar ratio of NaOH to HCl is 1:1. The reacting moles of HCl are 1/1 × 3.0 × 10⁻³ mol = 3.0 × 10⁻³ mol.
Step 4: Calculate the concentration of HCl
3.0 × 10⁻³ mol of HCl are in 25 mL of solution.

Answer;
-Two chlorine atoms
Explanation;
A barium atom attains a stable electron configuration when it bonds with two chlorine atoms.
-Barium is an alkaline earth metal, in group two of the periodic table. Like other alkaline earth metal it has a valency of two which means it reacts by loosing two electrons.
-Chlorine on the other hand is a halogen (group seven element) it reacts by gaining an electron, thus two chlorine atoms will require two electrons. Therefore, Barium would attain a stable configuration by loosing two electrons to two chlorine atoms.
Answer:
The answer to your question is: letter b Sulphur
Explanation:
Remember that in neutral molecules the sum of the oxidation numbers equals zero.
Mg⁺²S⁺⁶O⁻²₄
Magnesium = +2
Sulphur = +6
Oxygen = -2 x 4 = -8