What is the name given for the substance that reacts and forms in a chemical reaction?

State the law of conservation of mass.

Write the skeletal equation and balanced equation for the following reaction:

Potassium bromide (aq) + Barium iodide (aq) → Potassium iodide (aq) + Barium bromide (s)

Balance the following chemical equations:

(i) Mg(OH)₂ + HCl → MgCl₂ + H₂O

(ii) N₂ +H₂→ NH₃

(iii) P₄+O₂ → P₂O₅

Which of the following reactions is balanced, A or B?

A : 2NaCl+ 2H₂O 2NaOH + 2Cl₂ + H₂

B : Ca(OH)₂ + Cl₂→ CaOCl₂ + H₂O

What do the symbols (aq) and (s) indicate in a balanced chemical equation?

Identify the type of reaction:

(i) CH₄(g) + 2O₂(g) → CO₂(g)+ 2H₂O(g)

(ii) 2NaCI(l) 2Na(s) + Cl₂(g)

(iii) MnO₂ + 4HCI MnCl₂ + 2H₂O+ Cl₂

What happens when hydrogen gas is added to copper oxide?

Name one reaction which is accompanied by the evolution of heat.

Name the type of reaction for the following:

(i) Vegetable matter changing into compost.

(ii) Burning of natural gas.

Write the four factors responsible for the corrosion of iron.

Name one element in which corrosion is not proved to be wasteful.

What is breaking and making of bonds in chemical reaction called?

Which product is formed when carbon dioxide and water react in the same ratio?

Give an example of a reaction which is double displacement reaction as well as precipitation reaction?

Which kind of chemical reaction takes place when an electric current is passed through fused lead bromide?

Silver article gets black coating. Name the phenomenon.

Write any two chemical reactions in which water acts as a reducing and oxidising agent respectively.

Identify the type of chemical reaction in the following:

(i) A + B → C

(ii) A + BC → AC + B

(iii) A → B + C

(iv) AB +CD → AD +CB

Why is hydrogen peroxide kept in coloured bottles?

A shiny brown coin made up of an element turned black on heating. What was the element of the coin and what is the black compound formed?

Marble statues often slowly get corroded when kept in open for a long time. Give a suitable explanation.

What is the difference between skeletal equation and balanced chemical equation? Give example.

Complete the missing components/variables given as reactant and product in the following reactions:

What is redox reaction? Identify the substance oxidized and the substance reduced in the following reactions.

(i) CuO + H₂→ Cu + H₂O

(ii) MnO₂ +4HCl → MnCl₂ + Cl₂+ 2H₂O

Zinc oxide reacts with carbon, on heating to form zinc metal and carbon monoxide. Write a balanced chemical equation for this reaction. Name

(i) Oxidising agent

(ii) Reducing agent in this reaction.

With the help of an activity; demonstrate how do we know that a chemical reaction has taken place?

A water-insoluble substance X on reaction with dilute hydrochloric acid released a colourless and odourless gas accompanied by brisk effervescence. When the gas passed through water, the solution obtained turns blue litmus red. On bubbling the gas through lime water, it initially became milky and milkiness disappeared when the gas was passed in excess. Identify the substance X. Write the chemical equation of the reaction involved.

On the occasion of Diwali, Rohan used solution of calcium hydroxide (slaked) for white washing walls. After two or three days of white washing a compound is formed. This formed compound gives a shiny appearance to the walls. Read the above passage and answer the following questions.

(i) What is the chemical name of compound formed after 2-3 days of white washing?

(ii) Write the chemical reaction occurring during calcium hydroxide to a shiny appearance to the walls.

(iii) Name the type of reaction.

Which one of the following involves a chemical reaction?

Ethane (C₂H₆) on complete combustion gave CO₂ and water. It shows that the results are in accordance with the law of conservation of mass. Then, the coefficient of oxygen is equal to

A powdered salt (X) in a dry test tube was heated that evolves brown fumes of nitrogen dioxide and a yellow residue of lead oxide is also formed. The salt (X) is

A reddish brown coloured metal used in electric wires, when powdered and heated strongly in an open China dish, its colour rums black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on this information, the metal and black coloured substances are

When dilute sulphuric acid is added to pieces of iron sulphide, hydrogen sulphide gas is produced and soluble ferrous sulphate is formed. The type of chemical reaction involved is

Following reaction is used for the preparation of oxygen gas in the laboratory. Heat

2KClO₃(s) 2KCl(s) + 3O₂(g)

Which of the following statement(s) is (are) correct about the reaction?

A metal 'M' reacts with an acid according to the equation.

M + H⁺→ M³⁺ + H₂.

Which of the following is correct for metal M?

Which among the following statement (s) is/are true? Exposure of silver chloride to sunlight for a long duration turns grey due to

(i) the formation of silver by decomposition of silver chloride.

(ii) sublimation of silver chloride.

(iii) evolution of chlorine gas from silver chloride. (iv) oxidation of silver chloride.