The answer should be Pure substance
Answer : Option E) 50 grams.
Explanation : According to the solubility curves the compound 
to dissolve at 50 °C in 100 mL of water will need 50 grams of the compound. It is clearly indicated in the graph which is marked with red that at 50°C approximately 50.4 grams of the compound will be needed to dissolved in 100 mL of water to form a solution.
Carbon:
1s is filled. 2s is filled. 2p is shown to contain two electrons in one orbital and no electrons in the other two orbitals.
D is true because NO2 is a catalyst, and a catalyst is a compound which makes a reaction occur faster (not necessarily more effectively, creating more product, but it decreases the amount of time it takes).
Diamond for example, will not conduct electricity as there are no mobile ions or electrons to carry electric charge. all the electrons in the carbon atoms in diamond are used for covalent bonding.
another example is chlorine gas, there are also no mobile electrons to carry electric charge.
most covalent compounds cannot conduct electricity, but most ionic and metallic can. however, there are exceptions of course!
