MEDIUM
Earn 100

Hydrogen burns in air to form water is an example of _________ reaction.

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Important Questions on Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.

MEDIUM

A metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle.

Write a balanced equation for the reaction if one of the compounds formed is calcium chloride.

MEDIUM
What is observed when a pinch of sodium hydrogen carbonate is added to 2 mL of acetic acid taken in a test tube? Write the chemical equation for the reaction involved in this case. 
HARD
Match the chemical reaction given in the list-I with type of chemical reactions given in the list-II and select the correct answer from the options given below:
                 List-I (Chemical reactions)    List-II (Type of chemical reactions)
 I. CH3CH2OH acidified/K2Cr2O7  A. Addition
 II. C2H4 + H2 Ni catalyst  B. Elimination
 III. CH4g + Cl2g Sunlight  C. Redox
 IV. CH3CH2OH Heat, conc. H2SO4  D. Substitution

 

MEDIUM

Calcium oxide reacts vigorously with water to produce slaked lime.

CaOs+H2Ol CaOH2aq

This reaction can be classified as:

(A) Combination reaction        (B) Exothermic reaction

(C) Endothermic reaction        (D) Oxidation reaction

Which of the following is the correct answer?

HARD
1 g of copper powder was taken in a China dish and heated. What change takes place on heating? When hydrogen gas is passed over this heated substance, a visible change is seen in it. Give the chemical equations of reactions, the name and the colour of the products formed in each case.