Advertisements
Advertisements
प्रश्न
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
Advertisements
उत्तर
- Silver articles turn blackish after some time of exposure to air. This is because silver undergoes corrosion when exposed to air containing hydrogen sulphide.
- Silver reacts with hydrogen sulphide in air to form a layer of silver sulphide \[\ce{(Ag2S)}\], which gives silver articles a blackish appearance.
संबंधित प्रश्न
Tinning : Tin : : Galvanizing : _________
Why do we apply paint on iron articles?
Explain why Iron sheets are coated with zinc during galvanization.
Choose the correct answer from the options given below:
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as
A. Smelting
B. Ore-dressing
C. Calcination
D. Bessemerisation
What special name is given to their corrosion of iron?
What type of chemical reaction is involved in the corrosion of iron?
State two conditions for the rusting of iron.
Fill in the following blank with suitable word:
The corrosion of iron is called ................
Why is an iron grill painted frequently?
What is corrosion?
Name any two metals which do not corrode easily.
Name an alloy of copper. State its chemical composition and any one use.
Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?
A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium
In stainless steel alloy, iron metal is mixed with:
(a) Cu and Cr
(b) Cr and Ni
(c) Cr and Sn
(d) Cu and Ni
If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate
Name the metal which is a constituent of blood pigment?
Write three methods of preventing rusting of iron.
Give a reason why rust turns moist red litmus blue.
Give reason for the following:
A suspension of rust is basic in nature.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
Corrosion of silver causes a black layer of _______.
To prevent corrosion of iron and steel _______ method is used.
Find the odd one out and give its explanation.
Write the name.
Method used to prevent corrosion of copper.
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Draw a neat labelled diagram.
Anodizing
Complete flow chart given below.
Write a molecular formula for rust.
State two conditions necessary for rusting of iron.
Identify the correct statement from the following:
Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?
A man painted his main gate made up of iron, to
- prevent it from rusting.
- protect it from sun.
- make it look beautiful.
- make it dust free.
Which of the above statement(s) is/are correct?
Galvanisation is a process used to prevent the rusting of which of the following?
Explain the following:
Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.
Give an example of a chemical reaction for the following situation:
Sound is produced
