<u>Answer:</u> The correct answer is Option C.
<u>Explanation:</u>
We are given some polyatomic ions with their oxidation states. Polyatomic ions are defined as the ions which are formed from more than 2 atoms.
We need to find out the chemical formula for ammonium phosphate.
For this, the polyatomic ions used are:
Ammonium ion - 
Phosphate ion - 
By using criss-cross method, the oxidation state of the ions are exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.
Thus, the chemical formula for this compound is 
Hence, the correct answer is Option C.
Answer:
MnO₄⁻ + 2 H₂O + 3 e⁻ ⇒ MnO₂ + 4 OH⁻
2 moles of H₂O are on the reactant side.
Explanation:
Let´s consider the following half-reaction.
MnO₄⁻ ⇒ MnO₂
This reduction of permanganate to manganese dioxide happens in a neutral medium. The oxidation number of Mn changes from +7 to +4. When we are in a neutral medium, we can balance the reaction using the ion-electron method either as we were in acid or in basic medium. In this case, to satisfy the condition is the task (<em>water on the reactant side</em>) we will balance this half-reaction as if it were in basic media. Since Mn is already balanced, we have to balance O. We will add as many moles of water as excess of oxygen there is on 1 side, and the double of OH⁻ on the other side. Finally, we add as many electrons as we need to balance it electrically.
MnO₄⁻ + 2 H₂O + 3 e⁻ ⇒ MnO₂ + 4 OH⁻
Answer:
This is polar
Explanation:
If the arrows are of different lengths, and if they do not balance each other, the molecule is polar.
If the arrangement is asymmetrical, the molecule is polar.
Hope this helped!!!
Answer:
The cube A is magnesium, the cube B is aluminum and the cube C is silver.
Explanation:
Density is defined by the expression 
where m is the mass and V is the volume, therefore:
- Density of the cube A:
- Density of the cube B:
- Density of the cube C:
Solving for mass:
And all the three cubes have the same mass, so:
Therefore:
(Eq.1)
(Eq.2)
Solving for 
in Eq.1:
Replacing values for the volume:
As we know the density of the aluminum is 
, so replacing this value for 
:
that is the density of the magnesium.
Solving for 
in Eq.2:
That is the density of the silver.
Therefore the cube A is magnesium, the cube B is aluminum and the cube C is silver.
