CBSE Class 10 Chemistry - CH2 Acids and Bases - Very Short Questions and Answers (#cbsenotes)

Acids and Bases  

Very Short Questions and Answers

Class 10 Science - Chemistry

Q1: What is an acid?

Answer: Acid is a compound which yields hydrogen ions (H⁺) or Hydronium (H₃O⁺) ions , when dissolved in water.


Q2: What is the pH value of acids?

Answer: Less than 7 (i.e. 0 to < 7)


Q3: What is the taste of acids?

Answer: Sour


Q4: What happens to blue litmus paper when it comes in contact with acid solution?

Answer: It turns into red.


Q5: On the basis of origin, how acids are classified as?

Answer: Organic acids and Mineral acids.

CBSE Class 8/10 - Metals vs Non-Metals (Comparison) (#cbseNotes)

Metals vs Non-Metals

Physical Properties Comparison

Property	Metals	Non Metals
Physical State	Most metals are solids at room temperature except mercury which is a liquid. Gallium and Cesium also changes into liquid at slightly above room temperature.	Non Metals exist in all states. Eleven are gases, bromine is liquid while others are solids.
Melting and Boiling Point	Generally have high melting and boiling points. (Exceptions are Gallium, Mercury, Sodium and Potassium.)	Generally they have low melting and boiling points. Exceptions are: Carbon, Boron and Silicon.
Density	They have high density except Sodium and potassium.	Low denisty (Diamond is an exception.)
Lusture	Metals shine and are lustrous.	Non-metalls appear dull. (Exceptions are Diamond, graphite and iodine.)

CBSE Class 10 - Science - Four New Elements Added In Periodic Table

Four New Elements Added In 

Periodic Table

Time to update Chemistry Textbooks. On December 30, IUPAC completes the verification of discoveries of four new chemical elements. It completes the 7 periodic row.

The atomic numbers of these four new elements are 113, 115, 117 and 118. Soon the new names will be given to these elements. At present these elements have temporary names i.e.

Ununtrium 113, 
Ununpentium 115, 
Ununseptium 117, 
Ununoctium 118 

CBSE Class 10 Science CHEMICAL REACTIONS AND EQUATIONS - Board Questions (2008-2014) and Answers

CHEMICAL REACTIONS AND EQUATIONS

Board Questions (2008-2014) and Answers

Q1(2008): What happens chemically when quick lime is added to water?

Answer: Quick lime is CaO which reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of heat.

                           CaO(s) + H₂O(l) → Ca(OH)₂(aq)

Q2: A student burns magnesium ribbon in the lab and observes a white powder falling on the table. What type of reaction has taken place and name the white powder?

Answer: It is a chemical reaction. The white powder formed is magnesium oxide (MgO).

Q3: What are the essentials of a chemical reaction?

Answer:

• It should be balanced and confirm to the law of conservation of matter
• It should be molecular
• It must refer to an actual chemical equation

Q4: How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal?

Answer: When a burning match stick is brought near the mouth of the test tube in which reaction is taking place, it will burn with popping sound. It detects the presence of hydrogen (H₂) gas.

Q5: What change in colour is observed when white silver chloride is left exposed to sunlight? What type of chemical reaction is this?

Answer: White silver chloride turns grey in sunlight. This is due to the decomposition of silver chloride into silver and chlorine by light.It is a photo-chemical decomposition reaction.

                2AgCl(s) —^Sunlight—→ 2Ag(s) + Cl₂(g)

Q6: Why is respiration considered as exothermic process?

Answer: In respiration heat is released so it is termed as an exothermic reaction.

                   C₆H₁₂O₆ + 6O₂ —→ 6CO₂ + 6H₂O + energy

Q7(2010):What is meant by skeletal equation?

Answer: The equation which is unbalanced because the mass is not the same on both sides of the equation, is a skeletal chemical equation for a reaction.

During exam, try to write chemical equations and chemical formulae in your answers wherever possible. It enhances visibility and gives you more scores.

Q8: Identify the type of reaction in the following example:

Na₂SO₄(aq) + BaCl₂(aq) —→ BaSO₄(s) + 2NaCl(aq)

Answer: A double displacement reaction.

Q9: Why are bags of chips flushed with nitrogen gas?

Answer: Chips manufacturers usually flush bags of chips with gas such as nitrogen to prevent the chips from getting oxidised.

Q10 : What is precipitation reaction?

CBSE Class 10 - Science - CH2 - Acids, Bases and Salts (Worksheet)

Acids, Bases and Salts

credits:clker.com

Worksheet

Fill in the Blanks

1. Blue litmus changes into red colour in the presence of_______.

2. The acid present in lemon juice is _______.

3. Red litmus changes into blue colour in the presence of ______.

4. The chemical name of Plaster of Paris is ___________ and its chemical formula is ____________.

5. Methyl orange gives __________ in basic medium while phenolphthalein gives _______.

6. Example for strong acid is ________.

7. Example for weak acid is ________

8. Example for strong base is_______.

9. Example for weak base is ____________

CBSE Class 10 - Science - CH2 - Acids, Bases and Salts (MCQs)

Acids, Bases and Salts

credits:clker.com

MCQs

Q1: The most commonly used indicator in laboratory is
(a) Methyl Orange
(b) Litmus
(c) Phenolphtalein
(d) Universal Indicator

Q2: Which gas is released when a metal reacts with an acid?

(a) Cl₂

(b) O₂
(c) H₂
(d) SO₂


Q3: The strength of acid depends upon

(a) density of the acid
(b) oxygen atoms present
(c) number of hydrogen atoms present in the molecule
(d) concentration of H+ ions furnished by the acid


Q4: Which statement is incorrect?

(a) Acids have pH more than 7
(b) Acids give H⁺ ions in water
(c) Acid conduct electricity in aqueous solution
(d) Acids turn blue litmus red.


Q5: Which of the following substance is antacid?

CBSE Class 10 - Science - CH3 - Metals and Non-Metals

Metals and Non-Metals

Q & A

Q1: List any five physical properties of metals.

Answer: Physical properties of metals are:

1. Metals are usually hard (exceptions are: sodium and potassium).
2. These are sonorous.
3. These are lustrous.
4. Metals exhibit malleability and ductility.
5. Mostly they are solids (exception is mercury)
6. They exhibit high tensile strength.
7. These have high densities.

Q2: Are metals electronegative or electropositive?

Answer: Metals are electropositive i,e. they form cations by loosing electrons.

Q3: Define Malleability.

Answer: Malleability is the property of a metal, by which it can be beaten into thin sheets.

Q4: Name a metal which can be cut with a knife?

Answer: Sodium

CBSE Class 10 - Science - CHEMICAL REACTIONS AND EQUATIONS (MCQs)

CHEMICAL REACTIONS AND EQUATIONS

MCQs

Q1: Which of the following is not a decomposition reaction?

(a) CaCO₃ → CaO + CO₂
(b) H₂ + Cl₂ → 2HCl
(c) H₂CO₃ → H₂O + CO₂
(d) 2KClO₃ → 2KCl + 3O₂

Q2: Which of the following is not an oxidising agent?

(a) Oxygen
(b) Conc. Sulphuric acid
(c) Chlorine
(d) Hydrogen


Q3: The oxidation reaction which produces heat and light is

(a) endothermic
(b) photochemical
(c) combustion
(d) exothermic

CBSE Class 10 - Science - CH 16 - Management of Natural Resources (Q and A)

Management of Natural Resources

Why do we need to use our resources carefully?

Q & A

Q1(CBSE 2011): What is coliform bacteria? What does its presence in water indicate?

Answer: Coliform is a group of bacteria which is found in human intestines. Its presence in water indicates contamination by disease-causing microbes. Its high presence in rivers and ponds elevates the risks of water borne diseases like gastroenteritis.

Q2(CBSE 2011): State two reasons of launching "Ganga Action Plan". Which bacteria was found in Ganga water indicating contamination?

CBSE Class 10 - CH4 - Carbon and Its Compounds (MCQs)

Carbon and Its Compounds

(MCQs)

Q1: Which of the following is an odd compound?

(a) Ethene
(b) Ethane
(c) Propene
(d) Acetylene

CBSE Class 10 - Science - CH5 - Periodic Classification of Elements (MCQs)

Periodic Classification of Elements

Circular Periodic Table
credits:wpclipart

MCQs

Q1(NCERT): Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.

(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.

CBSE Class 9/10 - Science - All about Names of the Chemical Elements

All about Names of the Chemical Elements

1. There are 115 chemical elements known today to the world. Only 90 are found in nature and the rest are artificially created.

2. A good number of elements are named after human beings and mythological figures.

CBSE Class 10 - Science - Ch14 - Sources of Energy

Sources of Energy 

(Q & A)

Q1: Fill in the blanks.
(a) Hydro power plants convert _________ energy of falling water into electricity.

(b) When wood is burnt in a limited supply of oxygen, ______ is left behind as residue.

(c) Gases like ______, _____, ______ and ______ are generated in a biogas plant.

(d) Biogas contains _____ % methane.

(e) To maintain the required speed of the turbine, wind speed should be higher than _____.

(f) To establish 1 MW generator, the wind energy farm needs about ___ hectares of land.

(g) Ocean Thermal Energy plants can operate if the temperature difference between the water at the surface and water at depths up to ______ km is _______ or more.

(h) ______ and _______ countries have number of power plants based on geothermal energy.

Answer:

CBSE Class 10 - Science - CH3 - Metals and Non-Metals (MCQs)

Metals and Non-Metals

MCQs

Check in Periodic Table
How many metals, non-metals and metalloids?

1. Which of the following is the best electrical conductor?

(a) Gold

(b) Silver

(c) Copper

(d) Aluminium

CBSE Class 10 - Science - CH2 - Acids, Bases and Salts

Acids, Bases and Salts

credits:clker.com

MCQs, NCERT Solutions, Q & A

Q1: The most commonly used indicator in laboratory is
(a) Methyl Orange
(b) Litmus
(c) Phenolphtalein
(d) Universal Indicator

Answer:  Universal Indicator



Q2: Olfactory indicators are:
(a) Clove
(b) Turmeric
(c) Soap
(d) Rose Petals

Answer: (a) Clove

How to learn naming Chemical Formulae?

Chemicals
(src:deviantart)

Nomenclature of Simple Inorganic compounds.

1. A formula is a shorthand notation used to identify the composition of a molecule or compound.

2. For example chemical formula of water is H₂O. It includes the symbol of each element (e.g. Hydrogen:H and Oxygen:O)  in the molecule, along with numerical subscripts to show how many atoms of each element are present.

3. Most of the inorganic compounds are binary compounds i.e. it consists of two elements. Some are ternary i.e. contain more than two elements.

Class 10 - Science - Ch1 - Chemical Reactions & Equations

Ch1 - Chemical Reactions & Equations

MCQs, Q & A, NCERT Solutions

Q1:  A chemical reaction involves in
a. Only breaking of bonds
b. Only formation of bonds
c. Both breaking and formation of bonds
d. None of these

Answer: (c)  Both breaking and formation of bonds

Q2: A balanced chemical equation always obeys
a. Law of conservation of mass
b. Law of thermal equilibrium
c. Law of conservation of energy
d. All of the above

Answer: (a) law of conservation of mass.

CBSE- Class X - Ch5 - Periodic Classification of Elements

Periodic Classification of Elements 

(Chapter Notes and CBSE exam questions and answers)

Modern Periodic Table

Vertical Columns or Groups
There are 18 groups in the periodic table.

1. First group elements are called alkali metals.
2. Second group elements are called alkaline earth metals. They are not as soft as Group 1.
3. Groups three to twelve are called transition elements.
4. Group 1, 2 and 13 - 18 are called normal elements or main group elements or representative elements.
5. Group 16 elements are called chalcogens (except polonium).
6. Group 17 elements are called the halogen family.
7. Group 18 elements are called noble elements (earlier called inert gas group).
8. The lanthanides and actinides which form part of group 3 are called inner transition elements.

Horizontal Rows or Periods
Horizontal Rows are called periods in the Periodic Table. There are seven periods or rows.

CBSE - Class 10 - Ch4 - Soaps and Detergents

Soaps and Detergents

Soap & Detergents (Concept Map)

Q1: Why soap does not work well with hard water containing Ca²⁺ or Mg²⁺ ions?

Answer: Because it reacts with Ca²⁺ or Mg²⁺ to forma white precipitate which is called scum and soap goes waste. Therefore soap forms no or little lather with hard water.

Class 10 - Chapter 4- Carbon and its Compunds (Short Questions & Answers)

Class 10 - Chapter 4- Carbon and its Compounds

Methane Structure

(Short Questions & Answers)

Q1: State whether the following are true or false
       a. Both alkenes and cyclo-alkanes both can be represented by the same general formula.
       b. The general formula C_nH_2n is valid for any alkene with any number of multiple bonds,
       c. Acetone is the common name of propanone.
       d. Isomers always show same chemical properties.


Q2: Which is the common name for ethyne?

Q3: The complete combustion of a hydrocarbon always gives .....?

Q4: What is the term used for the compounds which have same molecular formula but
       different structures?