Explanation:
Molar mass of HBr = 81 g/mol
Molar mass of nitrogen dioxide gas = 46 g/mol
Molar mass of ethane = 30 g/mol
Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

So, the gas with least molar mass will effuse out fastest from the container and that is ethane gas.
The formula for average kinetic energy is:

where,
k = Boltzmann’s constant = 
T = temperature = 273.15 K ( at STP)
As we can see from the formula that kinetic energy depends upon only temperature of the gas molecule.
So, from this we can say that all the gas molecules have the same average kinetic energy at this temperature.
Because the cord is wrapped in rubber or plastic and they are not good conductors
Answer:
reactivity:very reactive,less reactive
density:float in water,sink in water
melting and boiling point:low,high
colour of salts: colourless,often coloured
It's a trick question because all of them contain both iconic and covalent bonds.
Hope it helps!! :) have fun
think yesu ckers isn't an isomer