Because the rate at which water vapour condenses gets increase slowly to get equal to the rate of evaporation of the water.
Explanation:
When a bottle is partly filled with liquid water is leaves space for vapours to escape and get condensed equally.
When sealed and kept below the lamp the rate of condensation increases due to the empty space in the bottle for getting vapours cool down.
A point arrives when evaporation equates the condensation of the liquid in bottle becomes stable because vapours cannot pass the bottle eventually condense and become liquid.
 
        
             
        
        
        
Answer:
See explanation and image attached
Explanation:
A bond line structure refers to any structure of a covalent molecule wherein the covalent bonds present in the molecule are represented with a single line for each level of bond order.
The bond-line structure of CH3CH2O(CH2)2CH(CH3)2 has been shown in the image attached. We know that oxygen has a lone pair of electrons and this has been clearly shown also in the image attached.
 
        
             
        
        
        
Answer: Option (c) is the correct answer.
Explanation:
HF is a weak acid and not a strong acid. This is because fluorine is a highly electronegative atom and when it combines with a hydrogen atom then it will attract the valence electron of hydrogen atom more towards itself. 
As a result, it will not dissociates easily to give hydrogen ion. Hence, it acts as a weak acid.
A neutralization reaction is defined as a reaction in which an acid reacts with a base to give salt and water. For example, 
It is true that, spectator ions "appear in the total ionic equation for a reaction, but not in the net ionic equation".
Titration is defined as a process in which concentration of an unknown solution is determined using a solution of known concentration.
Thus, we can conclude that the statement HF, HCl, and HNO3 are all examples of strong acids, is false.
 
        
             
        
        
        
Since the given solubility is 350 ppm, convert it first with fraction of solubility. by dividing the solubility with 10^6
S = 350 / 10^6
s = 3.5 x 10^-4
the multiply it to the total solution to calculate the amount of substance present
m = ( 3.5 x 10^-4 ) ( 1.01 )
m = 3.535 x 10^-4 g of the substance present