Ionic compounds are those compounds which form an ion or
dissociates into ions when placed in a solution. These compounds are made up of
a metal and non metal. From the choices, here are the ionic compounds:
na2so4
h2so4
cacl2
<span>ca3(po4)2</span>
mitochondria
im not 100% sure but it makes sense
Answer: The correct option is 3.
Explanation: We are given a compound which is made up of iron and oxygen only. The ratio of the two are given as:

This means that, number of iron ions are 2
Number of oxide ions are 3
From the above information, the formula becomes : 
The valency of iron = 3
Valency of oxide = 2
This compound is named as iron (III) oxide.
Hence, the correct option is 3
Pressure of the gas P1 = 30.7 kpa
When it doubled P2 = 61.4 kpa
Temperature T1 = 0 => T1 =. 0 + 273 =273
Temperature T2 =?
We have pressure temperature equation P1T1 = P2T2
=> T2 = P1T1 / P2 = (30.7 x 273) / 61.4 = 136.5
So the temperature for doubling the pressure is 136.5.