LBr is ionic compound because k for potassium is metal which means it’s on the left side of the periodic table and Br which is bromine is a non metal which means is on the right side of the periodic table.
In Conclusion when a non metal and metal come together the are called ionic compound
<u>a) Answer: </u>
<em>Number of molecules in 1 mole</em>
<u>Explanation:</u>
a) Whether we take any of the substance among all three of the given substances they will have the same number of molecules in 1 mole of the substance is considered and the value for this will be 
<u>b) Answer: </u>
<em>In the given question </em><em>mass of the substance</em><em> which is </em><em>greatest</em><em> is asked for </em><em>one mole</em><em> and we also know that </em><em>mass of one mole is given by molar mass. </em>
<u>Explanation:</u>
b) It is known that
is the molar mass for oxygen which is greater than that of hydrogen while fluorine has a molar mass of
which on comparison shows that, it is the highest amongst all three.
Answer: Rate of decomposition of acetaldehyde in a solution is 
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
For a reaction : 
![Rate=k[A]^x](https://tex.z-dn.net/?f=Rate%3Dk%5BA%5D%5Ex)
k= rate constant
x = order of the reaction = 2


Thus rate of decomposition of acetaldehyde in a solution is