The HCl added = 1.25 moles
and the moles of Na2HPO4 = 1 mole
Now when acid is added in the given solution of Na2HPO4
One mole of H+ will react with one mole of Na2HPO4 to given one mole of NaH2PO4
Na2HPO4 + H+ ---> NaH2PO4
Now this one mole formed NaH2PO4 will further react with 0.25 moles of H+ left to form 0.25 moles of H3PO4 and 0.75 moles of NaH2PO4 will remain in the solution
So this will result into formation of a buffer of phosphoric acid and NaH2PO4
NaH2PO4 + H+ ---> H3PO4
pKa of H3PO4 = 2.1
so pH = pKa + log [salt] / [acid] = 2.1 + log [0.75 / 0.25] = 2.58
so the pH will be in between 2.1 to 7.2
Answer:
ρ = 1.08 g/cm³
Explanation:
Step 1: Given data
Mass of the substance (m): 21.112 g
Volume of the substance (V): 19.5 cm³
Step 2: Calculate the density of the substance
The density (ρ) of a substance is equal to its mass divided by its volume.
ρ = m / V
ρ = 21.112 g / 19.5 cm³
ρ = 1.08 g/cm³
The density of the substance is 1.08 g/cm³.
Igneous Rocks are formed from the cooling of magma or lava.
Answer:The visible light contains 7 colours : Violet, indigo, Blue, Green, Yellow, Orange and Red.
White colour is formed by the interference of all 7 colours, thus white light has the combination of all frequencies of visible light.
Explanation:
Answer:
1400KJ/mol⁻¹
Explanation:
Amount of heat required can be found by:
Q = m × c × ΔT
<em>Where m is the mass, c is the specific heat capacity (4.2KJ for water) and ΔT is the change in temperature.</em>
Q = 24 × 4.2 × (23 - 9)
= 24 × 4.2 × 14
= 1411.2KJ/mol⁻¹
= <u>1400KJ/mol⁻¹</u> (to 2 significant figures)