SCIENCE IMPORTANT QUESTIONS FOR CLASS 10TH
CHAPTER – 2
When acid reacts with metal, which gas is usually released ? Explain with an example. How will you check the presence of this gas ?
Why does aqueous solution of acid conduct electricity ?
Why should plaster of Paris be kept in a moisture – proof pot ? Explain it.
Baking soda washing soda and two – two major use tell.
Take a strip of magnesium of equal length in test tube ‘A’ and ‘B’ . Add hydrochloric acid (HC l ) in test tube ‘A’ and acetic acid (CH 3 COOH) in test tube ‘B’ . The amount and concentration of both acids are the same. Which test tube will bubble faster and why ?
When diluting the acid, why do they recommend that the acid should be mixed with water and not water with acid?
Fresh milk has a pH value of 6 . What will be the change in its pH value when yoghurt is made ? Explain your answer.
Why do HC l , HNO 3 etc. show acidic properties in aqueous solution while solutions of compounds like alcohol and glucose do not show acidity properties ?
For the following reaction, first write the word – equation and then the balanced equation :
(a) Dilute sulfuric acid reacts with granular zinc.
(b) Dilute hydrochloric acid reacts with magnesium strip.
(c) Dilute sulfuric acid reacts with aluminum powder.
Baking powder is used to make cakes. If you use baking soda to make your mother’s cake at home , then –
(a) How will this affect the taste of the cake and why ?
(b) How can baking soda be converted into baking powder ?
(c) What is the significance of adding tartaric acid to baking soda ?
Dry tablets of a common base B become sticky when placed in the open air. It is a product of alkali chlor – alkali process. Identify ‘B’ . What type of reaction occurs when B is reacted with an acidic oxide ? Write a balanced equation of chemical reaction.
Carbonate X of a metal reacts with an acid to form a gas which flows into a solution Y to form metallic carbonate again. On the other hand a gas G which is obtained at the anode at the time of electrolysis of salt solution , if flowed on dry Y , forms a compound Z which is used to disinfect drinking water. Identify X, Y, G and Z.
The sulphate salt of an element of group two of the periodic table is a white and soft substance. It can be molded into any shape by making its pulp. If this compound is left in the air for some time it forms a solid. Which cannot be used for molding purposes. Identify this sulphate salt and explain why it behaves like this . Also give equations of related reactions.
Salt ‘A’ is commonly used in making bakery products. When heated, it is converted into another salt ‘B’ which is used to remove the hardness of water itself and a gas ‘C’ is released. When this gas is flowed in lime water, it makes it milky. . A, B and C of the Spot.
How to differentiate baking powder and baking soda by heating ?
What do you mean by strong acids and weak acids ? Sort strong acid and weak acid from the following –
Hydrochloric acid , citric acid , formic acid , sulfuric acid , acetic acid and nitric acid.
What does it mean to have crystalline water in a substance ? Activity shows that crystalline water is present in the blue crystals of copper sulphate ?
Explain why , aqueous solution of sodium chloride is neutral but aqueous solution of sodium carbonate is alkaline ?
Describe the chlor – alkali method for making sodium hydroxide . Why is it called chlor – alkali reaction ?
CHAPTER-3
Write the electron point structure for sodium , oxygen and magnesium.
Distinguish between metals and non-metals on the basis of chemical properties.
Name three ways to protect iron from rust.
What are amphoteric oxides ? Give an example of two bipolar oxides.
Give reasons –
i) Platinum , gold and silver are used to make jewelery.
ii) Sodium , Potassium and Lithium are stored inside the oil.
Copper is used to make hot water tanks but not steel. Explain the reason for this.
Name two metals which will displace hydrogen from dilute acid and two metals which cannot do so ?
You must have seen copper cleaning dirty dishes with lemon or tamarind juice. Why are these citrus substances effective in cleaning dishes ?
What is an alloy? Give an example of three alloys.
Write three properties of ionic compounds.
Question no. : 1
A compound X and aluminum are used to connect the railway lines
(a) Identify compound X.
(b) Write the name of this reaction.
(c) Write the chemical equation of this reaction.
A metal that remains in the liquid state at room temperature , it is heated in the presence of sulfide and oxygen is obtained. Identify this metal and its ore and write the chemical equation of the reaction that takes place.
You are given a hammer , battery , bulb , wire and switch.
a) How can you differentiate between samples of metals and non-metals using these?
(b) Assess the usefulness of these tests for differentiation between metals and non-metals.
Explain the following –
(a) elyuminiyaka ¼? A l ¿½ the activity decreases if it HNO 3 is immersed in.
(b) Cannot catalyze oxides of carbon , sodium or magnesium.
(c) Sodium chloride NaCl is not a good conductor of electricity in solid state , whereas it conducts electricity in dissolved state or in aqueous solution.
(d) Metals like Na, K, Ca and a Mg are never found independently in nature.
How do metals combine with oxygen to form oxides? Give the equation.
(a) Iron with steam
(b) Calcium and potassium with water
Explain the difference between ionic compounds and covalent compounds.
A person becomes a goldsmith in every house. He pretended to create the same shine in old and dirty gold ornaments as before. Without a doubt a woman gives him her gold bracelets which he puts in a special solution. The bracelets start shining like new but their weight is reduced drastically. That woman is very sad and after arguing the person has to bow down. Like a detective, can you tell us about the nature of that solution?
What is the reason that the melting point and statement of metals are high?
Write the major physical properties of metals.
A non-metallic ‘A’ which is the largest component of the atmosphere , when it is heated with hydrogen ( H 2 ) in the ratio of 1: 3 in the presence of Fe catalyst forms gas ‘B’ . When heated with oxygen it gives an oxide ‘C’ . If this oxide is carried in the presence of air in water then it forms an acid ‘D’ which acts as a strong oxidizer.
i- A, B, C, and D of the Spot.
ii- This non-metal is an element of which group of periodic table ?
CHAPTER – 4
What is homologous series ? Examples of well explaining.
What is the reason that diamond is hard and graphite is smooth and soft ? While both are similar to carbon.
What will be the point structure of the electron of carbon dioxide with the CO 2 formula ?
Draw electron point structure –
1. Ethanic Acid 2- H 2 S 3- F 2
Carbon of two properties which the are that cause us around the carbon compounds of huge numbers appear committed to ?
Why is carbon and its compounds used as fuel?
Both diamond and graphite are made of carbon atoms, yet inequality is found in their physical properties , why?
Construct the following electron point.
(a) CH 4 (b) N 2
What will be the electron point structure of a sulfur molecule made up of 8 atoms of sulfur?
answer the following questions.
(a) What bonds are found in carbon?
(b) Name the upper form of carbon?
(c) What is the valency of carbon ?
CHAPTER- 5
Compare the arrangement of the elements in the Modern Periodic Table and the Periodic Table of Madleaf.
How is the electronic configuration of the elements related to the position of the elements in the modern periodic table ?
In which element –
(a) There are two shells and both are complemented by electrons.
(b) The electron configuration is 2 , 8, 2 .
(c) There are total three shells and there are four electrons in the valence shell.
(a) Which properties of all elements of the column of boron in the periodic table are the same ?
(b) Which property of all elements of the column of fluorine in the periodic table is the same.
Which metals are in the first ten elements in the periodic table ?
Name: –
(a) Three elements whose outer shells are complete.
(b) Two elements with two electrons in their outermost shells.
What are the limitations of Dobereiner’s classification ?
What are the limitations of Newlands’ octave principle ?
Estimate the formula of the oxide of the following elements using the periodic table of mandrel :
K, C, Al, Si, Ba
Why do you think the noble gases are kept in a separate group ?
What criteria did Mandleaf adopt to prepare his periodic table?
Explain the shortcomings of your periodic table of mandalif.
One element is the element of group II covers a third of the periodic table , makes fury be basic oxides in the presence of oxygen.
(a) Identify that element
(b) Write the electron configuration of that element.
(c) When this element burns in the presence of a metal, write a balanced chemical equation of the reaction occurring at that time.
What criteria did Mendeleev use to prepare his periodic table?
Mendeleev predicted some elements that were not available at that time and named two of them – eka-silicon and eka aluminum.
(a) Write the names of those elements who took the place of these elements.
(b) Write the group number and the covered number of these elements in the modern periodic table.
(c) Classify these elements into metals / nonmetals / nonmetals .
(d) How many connective electrons are there in each of them.
The electronic configuration of an atom is 2 , 8 , 7.
(a) What is the atomic number of this element
(b) Which element would have chemical similarity with the following ?
N (7), F (9), P (15), Ar (18) ?
Write the names of two elements that exhibit chemical reactivity like magnesium.
Can the following groups of elements be classified as Dobereiner’s triad ? Explain with reason
(a) Na, Si, Cl (b) Be, Mg, Ca
Atomic mass, respectively : Be-9, Na – 23, Mg – 24, Si – 28, Cl – 35 and Ca – 40
Arrange the following elements in ascending order of their atomic radii –
(a) Li, Be, F, N
(b) Cl, At, Br, I
Identify and write the names of the metal elements from the following elements, whose electronic configuration is given below –
(a) 2, 8, 2 (b) 2, 8, 1 (c) 2, 8, 7 (d) 2, 1
Element ‘A’ ( atomic number 19) When combined with element ‘B’ ( atomic number 17) , write the formula for the compound that forms. Draw an electron point diagram of that compound. Explain the nature of the bond formed.
Name the following –
(a) Three elements with an electron in their outermost shell.
(b) Two elements with two electrons in their outermost shells.
(c) Three elements whose outer shell is complete.
