Previous years question of chemistry class 10th : PYQ's of chemistry class 10 chapter 2nd acid,bases and salt
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Previous years question of chemistry class 10th
Chapter - Acid, bases and salts
Q1). Name the three chemicals in which common salt used as the raw material.
Answer :- washingsoda, bleaching powder and baking soda are three chemicals in which common salt is used as raw material.
Q2). How does a strong acid differ from a concentrated acid?
Answer :- the strength of an acid depend upon its dissociation power whereas, concentration depends upon water content in acid.
Q3). Why does an aqua solution of an acid conduct electricity?
Answer :- an acid in the aqua solution produces h + ions and the corresponding negative ions. Due to the presence of the ions in the solution, it conduct electricity.
Q4). Is pH of washing soda less than 7 or more than 7?
Answer :- pH of washing soda is more than 7 because it is basic in nature.
Q5). What is a neutralisation reaction? give one example.
Answer :- neutralization is a reaction in which acid and bases combines to form a salt and water.
Example - Hcl + NaOH → Nacl + H2O
Q6). Why plaster of paris should be stored in a moisture proof container?
Answer :- plaster of paris should be stored in a moisture proof container because plaster of paris, a powder mass absorbs water to form a hard solid known as gypsum.
Q7). Why does dry HCL gas not change the colour of the dry Litmus Paper.
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Q8). While during an acid why is it recommended that the acid should be added to water and not water to the acid?
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Q9). Why should curd and sour substances not be kept in brass and copper vessels?
Answer :- There is acid in curd and other sour substance. When they are kept in brass and copper vessels the metal reacts with the acid to discharge hydrog,en gas and harmful product there by spoiling the food. That's the reason why curd and sour substances shouldn't be kept in brass and copper vessels.
Q10). What is the biological important of pH?
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