Answer:
that pressure is called atmospheric pressure or air pressure. It is the force exerted on a surface by the air above is as gravity pulls it to earth. atmospheric pressure is commonly measured with a barometer. In a barometer , a column of mercury is a glass tube rises ot falls as the weight of the atmospheric changes
Answer: Option (d) is the correct answer.
Explanation:
As it is known that like dissolves like. So, water being a polar compound is able to dissolve only polar compounds.
Hence, a compound that is ionic or polar in nature will readily dissolve in water. Whereas non-polar compounds will be insoluble in water.
As 
is a non-polar compound. Hence, it is insoluble in water.
On the other hand, 
is a polar compound due to difference in electronegativity of chlorine and carbon atom there will be development of partial charges. Hence, there will be dipole-dipole forces existing between them.
Whereas 
is an ionic compound and it will readily dissociate into ions when dissolved in water. Also, there will be ion-dipole interactions between sodium and nitrate ions.
Hence, will readily dissolve in water.
Thus, we can conclude that the compounds correctly arranged in order of increasing solubility in water are < < .
Answer : Option C) 0.3 mol of Gold.
Explanation : Amongst the options given in the question, 0.3 mol of Au is the greatest in mass in grams.
As 0.3 mol X atomic weight of Au (196.966) = 59.088 grams;
Silver has 0.5 mol X atomic weight of Ag (107.86) = 53.93 grams;
The other options are not relevant as they deal in the atomic range which has mass value very less as compared to the moles of elements.
Therefore, it is clear that Au has the greatest mass amongst the given choices.
Change(A chemical reaction.)
