This topic breaks down the chemical dynamics of seawater. It analyzes the spatial and vertical distribution of salinity, the role of density gradients (halocline), and how geographic landlocking affects regional salinity variations.
Correct Answer:
(B) Land
Main source of the salinity of sea water is the land. While rivers bring various types of salt contents towards the sea, other factors which regulate the salinity of the sea are Vaporization, wind, river water, rain, oceanic currents and the volcanos etc. Average salinity of the sea is about 35‰.
Ques: 2
The highest salinity is found in :
Correct Answer:
(D)
Lake Van in Turkey
Among the lakes and seas given in the question, Van lake of
Turkey has maximum salinity which is 330‰.
Salinity in the Dead Sea = 238‰
Salinity in the Red Sea = 36-41‰
Salinity in Great Salt Lake = 220‰
Ques: 3
Which one of the following denotes water salinity gradient?
Correct Answer:
(B) Halocline
Halocline is a zone in the oceanic water in which salinity changes rapidly with depth. So, Halocline denotes water salinity gradient.
Ques: 4
Which of the following seas has the highest average salinity?
Correct Answer:
(D)
Dead Sea
Among the given options Dead sea has the highest average salinity (238‰). Assal lake has the highest average salinity in the world i.e. 348‰.
Ques: 5
Which one of the following salts contributes maximum to the salinity of sea water:
Correct Answer:
(D)
Sodium chloride
In 1884, during Challenger expedition, William Dittmar produced a report about the chemistry of sea water. He revealed in the report that there are 27 types of salts present in the sea water among which 7 are most prominent. These are as follows –
Salt Salinity (‰) Percentage (%)
Sodium Chloride 27.213 77.8
Magnesium Chloride 3.807 10.9
Magnesium Sulphate 1.658 4.7
Calcium Sulphate 1.260 3.6
Potassium Sulphate 0.863 2.5
Calcium Carbonate 0.123 0.3
Magnesium Bromide 0.076 0.2
Total 35 100
Notably percentage of average salinity in oceans is 35‰ and Sodium Chloride, plays major role in the salinity of the sea.
Ques: 6
Where is Great Salt Lake located ?
Correct Answer:
(B) U.S.A.
The Great Salt Lake is located in Utah province of the United States of America. The salinity of this lake is 220‰.
Ques: 7
The average salinity of water of Arabian Sea is-
Correct Answer:
(B) 35 ppt
Between 0o -10o latitudes in the Indian Ocean, the salinity is 35.14‰ but in the Bay of Bengal, it decreases to 30‰. At the same time salinity of Arabian Sea is found to be 36‰ because of comparatively dry weather, more vaporization takes place and water brought by rivers is also less. Therefore, option (b) is correct.