Answer:
9.28
Explanation:
pOH refers to a measure of hydroxide ions concentration. pOH tells about the alkalinity of a solution. If pOH is less than 7 then aqueous solutions are alkaline, acidic if pOH is greater than 7 and neutral if pOH is equal to 7.
Concentration of the hydroxide ions = 1.9 x 10-5 M
pH = 
pOH = 14 - pH
=14 - 4.72 = 9.28
MgCl₂ & PbSO₄ is the correct product for the given double replacement reaction.
<h3>What is double displacement reaction?</h3>
In the double displacement reaction displacement of two substrate will take place among two reactants and formation of products takes place.
In the question, PbCl₂ reacts with MgSO₄ and displacement between the cations takes place and formation of MgCl₂ and insoluble precipitate PbSO₄ is formed.
Given reaction is represented as:
PbCl₂ + MgSO₄ → MgCl₂ + PbSO₄
According to the activity series, reactivity of Magnesium is more as compared to the lead atom. So lead is displaced by the magnesium atom and form the above given products.
Hence, option (3) is correct i.e. MgCl₂ & PbSO₄.
To know more about double displacement reaction, visit the below link:
brainly.com/question/26413416
<h3>
Answer:</h3>
18.9 g F₂
<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Chemistry</u>
<u>Atomic Structure</u>
- Reading a Periodic Table
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
3.00 × 10²³ molecules F₂
<u>Step 2: Identify Conversions</u>
Avogadro's Number
Molar Mass of F₂ (Diatomic) - 38.00 g/mol
<u>Step 3: Convert</u>
- Set up:

- Multiply:

<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 3 sig figs.</em>
18.9306 g F₂ ≈ 18.9 g F₂