ANY IMPORTANT QUESTION FOR SCIENCE???? (CLASS10 BOARDS)
Answers
ANSWER:-⭐⭐❣❣
➡️Structure and function of Neuron
➡️ Cleaning action of Soap
➡️why Carbon form covalent bonds
➡️Explain mechanism of breathing in humans
HOPE IT HELPS YOU✔✔✨✨✌✌
Answer:
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Important Short Answer Type Questions
Q. (a) What are ‘magnetic field lines’? How is the direction of a magnetic field at a point determined ?
(b) Draw two field lines around a bar magnet along its length on its two sides and mark the field directions on them by arrow marks.
Ans.
(a) The magnetic field lines are the pictorial representation of the strength and direction of the magnetic field.
The direction of the magnetic field at a point can be found by placing a small magnetic compass at that point. The north end of the needle of a compass indicates the direction of magnetic field at a point where it is placed.
(b) Magnetic field lines of a bar magnet emerge from the north pole and terminate at the south pole. Inside the magnet, the field lines emerge from the south pole and terminate at the north pole, as shown in the given figure.
magnetic field lines
Q. (a) Mention the pH range within which our body works. Explain how antacids
give relief from acidity. Write the name of one such antacid.
(b) Fresh milk has a pH of 6. How does the pH will change as it turns to curd? Explain your answer.
(c) A milkman adds a very small amount of baking soda to fresh milk. Why does this milk take a longer time to set as curd?
(d) Mention the nature of toothpastes. How do they prevent tooth decay?
Ans.
(a) Our stomach has pH equal to 2. Antacids neutralize the excess of acid in our body and gives relief from hyperacidity. Sodium hydrogencarbonate is one of such antacid.
(b) pH will decrease as it turns to curd because curd is acidic due to the presence of lactic acid.
(c) It takes longer time to set as curd as bacteria do not work well in presence of sodium hydrogencarbonate, i.e. fermentation will take place slowly.
(d) Toothpastes are basic in nature. They neutralize the acid formed in mouth which causes tooth decay.
Q. Atoms of eight elements A. B. C. D, E, F. G and H have the same number of electronic shells but different number of electrons in their outermost shell. It was found that elements A and G combine to form an ionic compound. This compound is added in a small amount to almost all vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are acidic. The oxide of D is almost neural. Based on the above information answer the following questions:
(i) To which group or period of the periodic table do the listed elements belong?
(ii) What would be the nature of compound formed by a combination of elements B and F?
(iii) Which two of these elements could definitely be metals?
(iv) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(v) If the number of electrons in the outermost shell of elements C and G are 3 and 7 respectively, write the formula of the compound formed by the combination of C and G.
Ans.
(i) The listed chemicals belong to third period; it includes Na, Mg, Al, Si, P, S, Cl& Ar.
(ii) Compound formed by the combination of B (Mg) and F (S) will result in formation of salt called MgSO4
(iii) Compound A (Na) and B (Mg) are definitely metals as their oxides are basic in nature.
(iv) Element H (Ar), is likely to be found in gaseous state at room temperature as it is the 8th element of the group so it would have 8 electrons in its outermost shell which is the electronic configuration of an Nobel gas.
(v) They will form AlCl3 (Aluminium chloride)
Get here the complete set of CBSE Class 10 Science: Important Long Answer Type Questions
Important Practical Based Questions
Here you will get the important questions based on practical skills. In Section A of CBSE Class 10 Science Exam Paper 2020, you may find some questions which are designed to test your practical knowledge. So, to acquire sufficient practical skills, practice the questions provided below:
Q. Mention the essential material (chemicals) to prepare soap in the laboratory. Describe in brief the test of determining the nature (acidic/alkaline) of the reaction mixture of saponification reaction.
Ans.
Raw Materials Required For preparation of soap in laboratory are :
Vegetable oil
Sodium Hydroxide
Commom salt
Test to determine the nature of reaction mixture: When a red litmus paper is dipped in the reaction mixture, the paper changes its colour to blue. Hence, the reaction mixture of the saponification reaction is basic in nature.
Q. Write two precautions to be taken while identifying different parts of an embryo of a dicot seed.
Ans.
(i) The slide should be properly focused.
(ii) Slide should be observed first under low-power magnification and then under high-power magnification of the compound microscope.
Q. A student is to conduct an experiment to show CO2 is released during respiration. List two precautions that he/she must take for obtaining correct observation.
Ans.
Two precautions to be taken are:
(i) Germinating seeds (living) should be used.
(ii) The experiment set up must be air-tight.