Chemical Changes in the Lab

which of the following is not a physical change

• boiling of water to give water vapour

• melting of ice to give water

• dissolution of salt in water

• combustion of LPG

Tags

NGSS.MS-PS1-5

which of the following observation helps to determine that chemical change has taken place

• change in temperature

• change in colour

• evolution of a gas

• all of these

Tags

NGSS.MS-PS1-2

which among the following is a double displacement reaction

• lead reacts with copper chloride to give lead chloride and copper

• sodium sulfate reacts with barium chloride to form barium sulfate and sodium chloride

• carbon reacts with oxygen to carbon dioxide

• methane burns to give carbon dioxide and water

A dilute ferrous sulfate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct observation?

• Potassium permanganate is an oxidising agent, it oxidizes ferrous sulfate

• Ferrous sulfate acts as an oxidising agent and oxidizes potassium permanganate

• The color disappears due to dilution and no reaction is involved

• none of these

Tags

NGSS.HS-PS1-2

The gas liberated due to the heating of ferrous sulfate is

• Sulphur dioxide

• sulphur dioxide and sulphur trioxide

• oxygen

• nitrogen dioxide

Brown fumes obtained when lead nitrate on heating is

• oxygen gas

• nitrogen gas

• nitrogen dioxide

• hydrogen gas

Decomposition of silver chloride into silver and chlorine is an example of

• thermal decomposition

• photolytic decomposition

• electrolytic decomposition

• none of these

Nitrogen gas is filled in chip packets to avoid

• reduction

• oxidation

• combination

• combustion

MnO2 + 4 HCl → MnCl2 + Cl2 + 2 H2O. In this reaction reducing agent is

• Hydrochloric acid

• manganese dioxide

• chlorine

• water

H₂S + Cl_{2 -->} S + 2HCl. In this reaction, the oxidising agent is

• hydrogen sulphide

• chlorine

• sulphur

• hydrogen chloride