what do you mean by corrosive nature of metals? corrosive nature of acid is not related to the strenth.explain
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In fact metals by nature are not corrosive on their own. Rather many of them are corroded slowly or rapidly by various agents present around them. Many metals are corroded naturally by air and moisture like iron (Fe) while noble metals like Au and Pt are not. Ag first gets tarnished (darkened) in air and this ends up in corrosion.
Corrosion of metals is mainly due to formation of their oxides, sulphides on their surface. This is known as rusting in case of Fe. Excessive rusting plaques Fe metal and causes loss of metallic weight. All types of corrosion always cause net loss of metallic weight.
So corrosion means loss of matter due to chemical reaction. Yes, acids are generally corrosive. Because they react with elements and causes loss of weight. Corrosiveness of acids of course vary. It is not always related to their strength. It depends upon whether the acid is oxidative or reductive in nature. For example Sulfuric acid (1) is oxidative while Hydrochloric acid (2) is reductive. Both causes corrosion, especially to metals.
Metals are corroded by 1 due to formation of oxides while the same by 2 is due to formation of chlorides. Most of the metal chlorides are soluble in water so they don't deposit on the metal surface but causes weight loss to the metals. Similarly, most of the oxides are insoluble so they deposit on the surface forming oxide layer - also a case of weight loss.
Often, corrosion of certain metals by oxyacids are used to our advantage. Highly corrosive oxyacids are transported in Al container because formation of Aluminium oxide on the metal surface works like a rock solid protective layer and thus the acid does not corroded the metal further.
Corrosion of metals is mainly due to formation of their oxides, sulphides on their surface. This is known as rusting in case of Fe. Excessive rusting plaques Fe metal and causes loss of metallic weight. All types of corrosion always cause net loss of metallic weight.
So corrosion means loss of matter due to chemical reaction. Yes, acids are generally corrosive. Because they react with elements and causes loss of weight. Corrosiveness of acids of course vary. It is not always related to their strength. It depends upon whether the acid is oxidative or reductive in nature. For example Sulfuric acid (1) is oxidative while Hydrochloric acid (2) is reductive. Both causes corrosion, especially to metals.
Metals are corroded by 1 due to formation of oxides while the same by 2 is due to formation of chlorides. Most of the metal chlorides are soluble in water so they don't deposit on the metal surface but causes weight loss to the metals. Similarly, most of the oxides are insoluble so they deposit on the surface forming oxide layer - also a case of weight loss.
Often, corrosion of certain metals by oxyacids are used to our advantage. Highly corrosive oxyacids are transported in Al container because formation of Aluminium oxide on the metal surface works like a rock solid protective layer and thus the acid does not corroded the metal further.
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