(a) (i) No change will be on dry Litmus paper. (ii) The gas is sulphur dioxide (SO2), which turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid. (b) S(s) + O2(g) → SO2(g) Sodium dioxide SO2(g) + H2O(f) → H2SO3(aq) Sulphurous acid
(a) (i) No change will be on dry Litmus paper.
(ii) The gas is sulphur dioxide (SO2), which turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid.
It is easier to reduce a metal oxide into free metal. Since it is easier to obtain metals from their oxides than from their carbonates or sulphides directly, therefore, the carbonate and sulphide ores are first converted to oxides for extracting the metals.
It is easier to reduce a metal oxide into free metal. Since it is easier to obtain metals from their oxides than from their carbonates or sulphides directly, therefore, the carbonate and sulphide ores are first converted to oxides for extracting the metals.
Aluminium forms a non-reactive layer of aluminium oxide on its surface. This layer prevents aluminium to react with other substances. That’s why aluminium is used to make cooking utensils.
Aluminium forms a non-reactive layer of aluminium oxide on its surface. This layer prevents aluminium to react with other substances. That’s why aluminium is used to make cooking utensils.
Copper metal reacts with atmospheric carbon dioxide and forms copper carbonate and as a result, which copper vessel loses its shiny brown surface and forms a green layer of copper carbonate. Lemon or tamarind contain acid that neutralises the base copper carbonate and dissolves the layer. So, tarnisRead more
Copper metal reacts with atmospheric carbon dioxide and forms copper carbonate and as a result, which copper vessel loses its shiny brown surface and forms a green layer of copper carbonate. Lemon or tamarind contain acid that neutralises the base copper carbonate and dissolves the layer. So, tarnished copper vessels using lemon and tamarind, copper vessels retain their shine.
The gold metal is dipped in the solution of aqua regia i.e. 3:1 mixture of conc. HCl and conc. HNO3. Aqua regia is a fuming, highly corrosive liquid. It dissolves gold in it. When the gold ornaments are dipped into aqua regia, the outer layer of gold gets dissolved and the inner shiny layer appears.Read more
The gold metal is dipped in the solution of aqua regia i.e. 3:1 mixture of conc. HCl and conc. HNO3. Aqua regia is a fuming, highly corrosive liquid. It dissolves gold in it. When the gold ornaments are dipped into aqua regia, the outer layer of gold gets dissolved and the inner shiny layer appears. That is why the weight of gold ornaments drastically decreases.
Iron react with steam, whereas copper does not reat with cold water, hot water, or steam. So, hot water tanks are made of steel (an alloy of iron), then iron reacts with the steam formed by hot water. 3Fe + 4H2O → Fe3O4 + 4H2 Iron+ Steam --> Iron oxide + Hydrogen Therefore coppeRead more
Iron react with steam, whereas copper does not reat with cold water, hot water, or steam. So, hot water tanks are made of steel (an alloy of iron), then iron reacts with the steam formed by hot water.
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
(a) (i) No change will be on dry Litmus paper. (ii) The gas is sulphur dioxide (SO2), which turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid. (b) S(s) + O2(g) → SO2(g) Sodium dioxide SO2(g) + H2O(f) → H2SO3(aq) Sulphurous acid
(a) (i) No change will be on dry Litmus paper.
(ii) The gas is sulphur dioxide (SO2), which turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid.
(b) S(s) + O2(g) → SO2(g)
Sodium dioxide
SO2(g) + H2O(f) → H2SO3(aq)
Sulphurous acid
State two ways to prevent the rusting of iron.
Ways to prevent rusting of iron are : (a) By painting (b) By galvanizing
Ways to prevent rusting of iron are :
See less(a) By painting
(b) By galvanizing
What type of oxides are formed when non-metals combine with oxygen?
Non-metals when combine with oxygen form acidic oxides. For example: S(s) + O2(g) → SO2(g) (Acidic in nature)
Non-metals when combine with oxygen form acidic oxides.
For example:
S(s) + O2(g) → SO2(g)
(Acidic in nature)
Give reasons: Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
It is easier to reduce a metal oxide into free metal. Since it is easier to obtain metals from their oxides than from their carbonates or sulphides directly, therefore, the carbonate and sulphide ores are first converted to oxides for extracting the metals.
It is easier to reduce a metal oxide into free metal. Since it is easier to obtain metals from their oxides than from their carbonates or sulphides directly, therefore, the carbonate and sulphide ores are first converted to oxides for extracting the metals.
See lessGive reasons: Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Aluminium forms a non-reactive layer of aluminium oxide on its surface. This layer prevents aluminium to react with other substances. That’s why aluminium is used to make cooking utensils.
Aluminium forms a non-reactive layer of aluminium oxide on its surface. This layer prevents aluminium to react with other substances. That’s why aluminium is used to make cooking utensils.
See lessGive reasons: Sodium, potassium and lithium are stored under oil.
Sodium, potassium and lithium are very reactive and catch fire when exposed to air. This is due to their low ignition temperature and high reactivity.
Sodium, potassium and lithium are very reactive and catch fire when exposed to air. This is due to their low ignition temperature and high reactivity.
See lessGive reasons: Platinum, gold and silver are used to make jewellery.
Platinum, gold, and silver are used to make jewellery because they are very lustrous as well as they are very less reactive and do not corrode easily.
Platinum, gold, and silver are used to make jewellery because they are very lustrous as well as they are very less reactive and do not corrode easily.
See lessYou must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Copper metal reacts with atmospheric carbon dioxide and forms copper carbonate and as a result, which copper vessel loses its shiny brown surface and forms a green layer of copper carbonate. Lemon or tamarind contain acid that neutralises the base copper carbonate and dissolves the layer. So, tarnisRead more
Copper metal reacts with atmospheric carbon dioxide and forms copper carbonate and as a result, which copper vessel loses its shiny brown surface and forms a green layer of copper carbonate. Lemon or tamarind contain acid that neutralises the base copper carbonate and dissolves the layer. So, tarnished copper vessels using lemon and tamarind, copper vessels retain their shine.
See lessA man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
The gold metal is dipped in the solution of aqua regia i.e. 3:1 mixture of conc. HCl and conc. HNO3. Aqua regia is a fuming, highly corrosive liquid. It dissolves gold in it. When the gold ornaments are dipped into aqua regia, the outer layer of gold gets dissolved and the inner shiny layer appears.Read more
The gold metal is dipped in the solution of aqua regia i.e. 3:1 mixture of conc. HCl and conc. HNO3. Aqua regia is a fuming, highly corrosive liquid. It dissolves gold in it. When the gold ornaments are dipped into aqua regia, the outer layer of gold gets dissolved and the inner shiny layer appears. That is why the weight of gold ornaments drastically decreases.
See lessGive reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Iron react with steam, whereas copper does not reat with cold water, hot water, or steam. So, hot water tanks are made of steel (an alloy of iron), then iron reacts with the steam formed by hot water. 3Fe + 4H2O → Fe3O4 + 4H2 Iron+ Steam --> Iron oxide + Hydrogen Therefore coppeRead more
Iron react with steam, whereas copper does not reat with cold water, hot water, or steam. So, hot water tanks are made of steel (an alloy of iron), then iron reacts with the steam formed by hot water.
3Fe + 4H2O → Fe3O4 + 4H2
Iron+ Steam –> Iron oxide + Hydrogen
Therefore copper is used to make hot water tanks, and not steel.