A substance ‘X’ is used in white-washing and is obtained by heating limestone in the absence of air. Identify ‘X’.
1.CaOCl2
2.Ca (OH)2
3.CaO
4.CaCO3
Posted Date:-2021-12-02 16:39:42
Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is:
1.1 : 1
2.2:1
3.4:1
4. 1:2
Posted Date:-2021-12-02 16:54:04
In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?
1.2H2 (l) + O2 (l) > 2H2O(g)
2.2H2 (g) + O2 (l) > 2H2O (l)
3.2H2 (g) + O2 (g) > 2H2O (l)
4.2H2 (g) +O2 (g) > 2H2O (g)
Posted Date:-2021-12-02 17:02:46
Name the products formed when iron filings are heated with dilute hydrochloric acid
1.Fe (III) chloride and water (b) Fe (II)
2.chloride and water
3. Fe (II) chloride and hydrogen gas
4.Fe (III) chloride and hydrogen gas
Posted Date:-2021-12-02 16:56:44
Pb + CuCl2 → PbCl2 + Cu The above reaction is an example of:
1.combination
2. double displacement
3.decomposition
4.displacement
Posted Date:-2021-12-02 16:57:54
What type of chemical reactions take place when electricity is passed through water?
1.Displacement
2.Combination
3.Decomposition
4.Double displacement
Posted Date:-2021-12-02 16:46:41
When S02 gas is passed through saturated solution of H2S, which of the following reaction occurs?
1.SO2 + 2H2S → 2H20 + 3S
2.SO2 + 2H2S → H20 + 3S
3.SO2 + H2S → H2O + S
4.SO2 + H2O → SO3 + H2
Posted Date:-2021-12-02 16:55:05
Which of the following gases can be used for storage
1. Carbon dioxide or Oxygen
2. Nitrogen or Oxygen
3.Carbon dioxide or Helium
4.Helium or Nitrogen
Posted Date:-2021-12-02 16:59:33
3. Which of the following statements about the given reaction are correct? 3Fe (s) + 4H2O (g) → Fe3O4 (s) + 4 H2 (g) (i) Iron metal is getting oxidised (ii) Water is getting reduced (iii) Water is acting as reducing agent (iv) Water is acting as oxidising agent
1. (i), (zi) and (iii)
2.(in) and (iv)
3.(i), (ii) and (iv)
4. (ii) and (iv)
Posted Date:-2021-12-02 13:58:08
A dilute ferrous sulphate solution was gradu¬ally added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disap¬pears. Which of the following is the correct explanation for the observation?
1.KMnO4 is an oxidising agent, it oxidises FeSO4.
2.FeSO4 acts as an oxidising agent and oxidises KMNO4.
3.The colour disappears due to dilution; no reaction is involved.
4. KMnO4 is an unstable compound and de-composes in presence of FeSO4. to a colourless compound.
Posted Date:-2021-12-02 17:01:09
A substance added to food containing fats and oils is called:
1.Oxidant
2.Rancid
3.Coolant
4.Antioxidant
Posted Date:-2021-12-02 16:52:19
Give the ratio in which hydrogen and oxygen are present in water by volume.
1. 1:2
2.1:1
3.2:1
4.1:8
Posted Date:-2021-12-02 16:36:46
In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available, which of the following can be used in place of lead nitrate?
1. Lead sulphate (insoluble)
2.Lead acetate
3.Ammonium nitrate
4.Potassium sulphate
Posted Date:-2021-12-02 16:45:47
Magnesium ribbon is rubbed before burning because it has a coating of
1. basic magnesium carbonate
2.basic magnesium oxide
3.basic magnesium sulphide
4. basic magnesium chloride
Posted Date:-2021-12-02 13:57:20
MnO2 + 4HCl → 2 + 2H2O + Cl2 Identify the substance oxidized in the above . equation.
1.MnCl2
2.HCl
3.H2O
4.MnO2
Posted Date:-2021-12-02 16:38:39
Oxidation is a process which involves
1.addition of oxygen
2.addition of hydrogen
3.removal of oxygen
4.removal of hydrogen
Posted Date:-2021-12-02 16:32:26
Select the oxidising agent for the following reaction: H2S + I2 > 2HI + S
1. I2
2.H2S
3.HI
4.S
Posted Date:-2021-12-02 16:51:33
The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:
1.antioxidation
2.reduction
3.rancidity
4.corrosion
Posted Date:-2021-12-02 16:53:10
The horizontal rows of the periodic table are called ?
1.Groups
2.Periods
3.Sets
4.Matrices
Posted Date:-2021-12-02 13:44:07
The process of reduction involves
1.addition of oxygen
2.addition of hydrogen
3. removal of oxygen
4.removal of hydrogen
Posted Date:-2021-12-02 16:34:35
Three beakers labelled as A, B and C each containing 25 ml of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solution contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct? (i) In beakers A and B, exothermic process has occurred. (ii) In beakers A and B, endothermic process has occuBftd. (iii) In beaker C exothermic process has occurred. (iv) In beaker C endothermic process has occurred.
1. (i) only
2.(ii) only
3. (i) and (iv)
4.(iv), (ii) and (iii)
Posted Date:-2021-12-02 16:35:56
When Ag is exposed to air it gets a black coating of
1.AgNO3
2.Ag2S
3.Ag2O
4. Ag2CO3
Posted Date:-2021-12-02 16:40:43
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 decomposition of chlorine gas from silver chloride (iv) oxidation of silver chloride
1. (i) only
2. (i) and (iii)
3.(ii) and (iii)
4.(iv) only
Posted Date:-2021-12-02 16:37:40
Which metallic element is liquid at room temperature?
1.Zinc
2.Nickel
3.Lead
4.Mercury
Posted Date:-2021-12-02 13:44:59
Which of the following is an endothermic process?
1.Dilution of sulphuric acid
2.Sublimation of dry ice
3.Condensation of water vapours
4. Respiration in human beings
Posted Date:-2021-12-02 16:44:54