CBSE Guess Question Paper SCIENCE Class-10 Chapter 3. Metal and Non-metals

CBSE Guess Question Paper SCIENCE Class-10 Chapter 3. Metal and Non-metals

Q.1 Write an activity to show that ionic compounds are good conductors of electric current in their aqueous solution.

Q.2. Why is aluminum extracted from alumina by electrolytic reduction and not by reducing with carbon?

Q.3 Define the terms:(i) Mineral (ii) Ore and (iii) Gangue

Q.4. Explain how the following metals are obtained from their compounds by the reaction process:  (i) Metal ‘X’ , which is low in reactivity series. (ii) Metal ‘Y’, which is middle in reactivity series. (iii) Metal ‘Z’ which is high up in the reactivity series.

Q.5 Give reasons: (i) The surface of some metals acquires a dull appearance when exposed to air for a long time. (ii) A salt which does not conduct electricity in the solid state becomes a good conductor in molten state

Q,6 What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes places.

Q.7.You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

Q.8. Write a balanced chemical equation for the reaction of the following metals with water: (i) Ca (ii) Zn (iii) Fe

Q.9. What will happen if a : (i) Strip of zinc is immersed in a solution of copper sulphate. (ii) Strip of copper is kept immersed in a solution of silver nitrate

Q.10. Explain why: (i) Conc. HNO3 can be stored in aluminium container. (ii) Aluminium is used for making transmission wires. (iii) 24 carat gold can not be used for making ornaments. (iv) Aluminium is used for making cooking utensils. (v) Metals generally do not form compounds with hydrogen.

Q.11. An element X on reacting with O2 forms X2O.This Oxide dissolves in water and turns blue litmus paper red. Predict the nature of element whether it is a metal or a non metal.

Q.12 An element E combines with O2 to form an oxide E2O, which is a good conductor of electricity. Answer the following: i) How many electrons will be present in the outer most shell of E? ii) Write the formula of the compound formed when it combines with Chlorine.

Q.13 Name one electrovalent compounds in each case in which ; (i)One atom combines with one other atom  (ii)One atom combines with two other atoms (iii)One atom combines with three other atoms

Q.14 Why is ZnO called an amphoteric oxide? Give the support to your answer.

Q.15 Answer : a. Write the electron dot structure for oxygen and magnesium. b.  Show the formation of Na2O and CaO by the transfer of electrons.

Q.16 Give equation for the following (a) Iron is heated with steam. (b) Magnesium reacts with water. (c) iron reacts with dil.HCl

Q.17 A trivalent metal X is manufactured by the process of electrolysis, It is the most abundant metal in the earth’s crust. Identify the metal and state its two uses.

Q.18 Which gas is always produced when a metal reacts with a dilute Write chemical reaction when iron reacts with dil. H2SO4.

Q.19. What is the activity series of metals? Rearrange the following metals in an increasing order of reactivity: Aluminum, Zinc, Mercury.

Q.20 What is meant by the term ‘enrichment of ore’ ? name four Methods generallyused for enrichment of ores.

10th Chemical reaction and equation Practice Assesments

ASSIGNMENT : FIRST TERM (2012-2013)                                    X SUBJECT   : CHEMISTRY CHAPTER        : CHEMICAL REACTIONS AND EQUATIONS           Max Marks: 55

A. Very short answer questions: (1 mark each) (1x 14= 14 marks)

1. What are reactants ?

2. What are products ?

3. What is the term used for symbolic representation of a chemical reaction ?

4. What does the + sign between the reactants indicate ?

5. How is the salt solution in water indicated in a chemical reaction /

6. Aluminium burns in chlorine to form aluminum chloride. Write a balanced equation for this reaction ?

7. Balance the following equation and add the state symbols :

Zn(s) + 2HCl(aq) → ZnCl2 + H2

8. Name the following reaction.

AB + CD → AD + BC

9. Aluminium metal displaces iron from ferric oxide (Fe2O2) giving aluminium oxide and iron. Which is more reactive, aluminium or iron ?

10. Identify from the following reaction : H2S + Cl2 → 2HCl + S

a. Component oxidized

b. Oxidizing agent

11. Give one example of a redox reaction which is also a combination reaction.

12. Which atom is reduced on burning an element in air.

13. When SO2 gas is passed through saturated solution of H2S, the following reaction occurs

SO2 + 2H2S → 2 H2O + 3S

In this reaction, which substance is oxidized and which one is reduced.

14. In the following reaction between lead sulphide and hydrogen peroxide

PbS(s) + 4H2O(aq) → PbSO4(s) + 4H2O(l)

a. Which substance is reduced ?

b. Which substance is oxidized ?

B. Short answer questions: (2 marks each) (2x4=8)

1. Write a chemical equation for each of the following reactions :

a. Zinc metal reacts with aqueous solution of hydrochloric acid to form zinc chloride solution and hydrogen gas.

b. When solid mercury (II) oxide is heated, liquid mercury and oxygen gas are produced.

2. H2 + O → H2O is a balanced chemical equation. It is considered to be incorrect. Why? 3. Write balance chemical equations to represent the following statements :

a. Carbon (coke) burns in air to form carbon dioxide gas.

b. A piece of sodium metal on putting in water forms caustic soda and hydrogen gas.

3. Write the balanced chemical equations for the following chemical reactions :

a. Aqueous solutions of sulphuric acid and sodium hydroxide react to form aqueous sodium sulphate and water.

b. Phosphorus burns in chlorine gas to form phosphorus penta chloride.

4. Magnesium is more reactive than copper or iron but iron is more reactive than copper.

a. A solution of magnesium sulphate is put into a copper pot.

b. A solution of copper sulphate is put into a iron pot.

c. A solution of magnesium sulphate is put into a iron pot.

Which of the above pots will get damaged? Why? What is this reaction called?

C. Short answer questions: (3 marks each)(3x 4= 12)

1. What are the three essentials of a chemical equation ?

2. Explain the term reduction with examples.

3.A colourless lead salt, when heated, produces a yellow residue and brown fumes.

a. Name the lead salt.

b. Name the brown fumes.

c. Write a chemical equation of the reaction involved.

4. When a green iron salt is heated strongly, its colour finally changes to black and colour of burning  sulphur is given out.

a. Name the iron salt.

b. Name  the type of reaction that takes place during the heating of iron salt.

c. Write a chemical equation for the reaction involved.

D. Balance the following skeleton equation by hit and trial method : (2x6=12)

a. C2H4 + O2 → CO2 +H2O

b. C2H2 + O2 → CO2 +H2O

c. CH4 + O2 → CO2 +H2O

d. Al2(SO4)3 + NaOH → Al(OH)3  + Na2SO4

e. Cu2S + O2 → Cu2O +S2O

f.  AlN + H2O → Al(OH)3  + NH3

E Define: (1x9=9)

1. Rancidity      2. Combination reactions  3. Decomposition reactions 4. Double displacement reaction  5. Displacement reaction   6. Redox reaction     7. Corrosion  8. Oxidising agent   9. Reducing agent

MCQ: Fill in the blanks: Acid base and salt d salt

MCQ	Fill in the blanks:  Acid base and salt d salt
1.	The substances whose aqueous solution change the blue litmus to red ------------------Acids
2.	The substances having a tendency to lose one or more protons are called: ------------   Acids
3.	The substances which donate the pair of electrons for bond formation, are known as:-------     Base
4.	When equivalent quantities of acid and base are mixed, salt and water are formed, the reaction is termed as:----------- Neutralization
5.	The acids which contain one acidic hydrogen are called:-------- Mono-protic
6.	The number of acidic hydrogen atoms present in a molecule of an acid is called: ----  Basicity
7.	The number of replaceable [OH] ions present in a molecule of base, is called: ---    Acidity
8.	An acid that produces large number of (H) ions in aqueous solution is called: ---------Strong acid
9.	An ionic compound, that is formed when an acid neutralizes a base, is called:------ Salt
10.	SaIts that formed by the reaction of strong acid with weak base are:----Acidic
11.	Alums are example of  ---------salt:               Double salts
12.	The formula of Washing Soda is                                                  Na₂CO₃ 6H₂O
13.	Acids are the substances which give H+ ions aqueous solution, is the concept of:   Arrhenius
14.	Arrehenius theory of acid-base is not applicable in:     non — aqueous solution
15.	According to the Arrhenius concept, the strength of acid or base is based on their:   -------- a. rates of ionization          b. rates of dissociation
16	According to Bronsted — Lowry concept, a base is a substance which acts as:      a proton acceptor(NH₃)

CBSE ADDA: Chemistry:MCQ:Acid base and salt: For Olympiads

Multiple-Choice Questions: Acid base and salt

1.  The word acid comes from the Latin word ‘ acere ‘ which means

a)      Sweet

b)      Salty

c)      Neutral

d)      Sour

2. Substances which are bitter in taste, feel soapy on touching are known as

a)      Acids

b)      Bases

c)      Indicators

d)      Neutral solution

3. Special type of substances used to test whether a substance is acidic/basic are known as

a)      Indicators

b)      Acids

c)      Bases

d)      Salt

4. Some naturally occurring indicators are

(a). Turmeric

(b)  Litmus

©. China rose

(d). All the above

5.The most commonly used natural indicator’ Litmus’ is extracted from

(a).Lichens

(b). Turmeric

©. Indicators

(d). China rose

6. Litmus is available in the form of

(a). Litmus paper

(b) Lichens

©   Indicator

(d). China rose

7. Neutral solutions which do not change the colour of either red/blue litmus are known  as

(a).Neutral solutions

(b) Acid solutions

©. Basic solutions

(d). Neither acidic nor basic

8. Acetic acid is found in

(a).Curd

(b). Spinach

©  Citrus fruits

(d). Vinegar

9. Formic acid is found in

a). Curd

(b). Spinach

©. Ant’s sting

(d) Ascorbic acid

10. Citric acid is found in

(a). Curd

(b). Citrus fruits

©. Ascorbic acid

(d). Lime water

11. Lactic acid is found in

(a). Curd

(b).Citrus fruits

©.Gooseberry

(d)Lime

12. Oxalic acid is found in

a)      Spinach

b)      Curd

c)      Oranges

d)      Unripe mangoes

13. Ascorbic acid is found in

(a). Amla & Citrus fruits

(b) Curd

©.  Oranges & lemon

(d).Unripe mangoes

14. Tartaric acid is found in

(a). Tamarind

(b) Grapes

©  unripe mangoes

(d)All of the above

15. Calcium hydroxide is found in

Calcium carbonate

Calcium chloride

Calcium

Lime water

16. Ammonium hydroxide is found

(a).Window cleaner

(b).Detergents

(c)  Soap

(d). Milk of magnesia

17. Sodium hydroxide is found in

a)      Soap

b)      Window cleaner

c)      Calcium hydroxide

d)      Sodium

18. Potassium hydroxide is found in

(a). Soap

(b). Window cleaner

© Potassium

(d)Potassium chlorate

19. Magnesium hydroxide is found in

(a). Milk of magnesia

(b).Magnesium chloride

(c)  Magnesium ribbon

(d) Magnesium hydroxide

20.Which of the following salts is basic in nature?

(a) NH4NO3

(b) Na2CO3

(c) Na2SO4

(d) NaCl

Answer

1. D         2  b          3. A              4. D            5. A            6. A          7. A        8. d

9. C           10. b      11. A          12. A          13. A           14.  D         15. d         16. A

17. A      18. A             19.a         20 B