Which of the following is not a chemical reaction?
i) Chemical digestion involves the secretions of enzymes throughout your digestive tract. These enzymes break the chemical bonds that hold food particles together. This allows food to be broken down into small, digestible parts.
ii) As no chemical bonds are broken, and no new substances are formed when sugar is dissolved in water so, it is not a chemical reaction.
iii) Chemical changes require a change on a molecular level that cannot be reversed because they form some new substance. Souring milk is not something you can reverse, and the process of it souring produces new molecules.
iv) All the light a candle makes comes from a chemical reaction known as combustion in which the wax (made from carbon-based chemicals typically derived from petroleum) reacts with oxygen in the air to make a colorless gas called carbon dioxide.
In a redox reaction :
A chemical reaction in which electrons are transferred between two reactants participating in it. This transfer of electrons can be identified by observing the changes in the oxidation states of the reacting species.
The galvanisation of iron means coating iron with :
Galvanisation or galvanization (or galvanizing as it is most commonly called) is the process of applying a protective zinc coating to iron or steel, to prevent rusting.
Development of bad smell and taste in food item containing oil / fat is due to :
Rancidity refers to the spoilage of a food in such a way that it becomes undesirable (and usually unsafe) for consumption.
In the following chemical equation
Na2CO3 + xHCl → 2NaCl + CO2 + H2O.
The value of x is :
After balancing the equation:
Na2CO3 + 2HCl → 2NaCl + CO2 + H2O.
Which one of the following process involves chemical reaction
When copper is heated in the presence of air in a very high temperature,a chemical reaction takes place. In this situation,the highly heated copper reacts with the oxygen of the air to form a thin layer of copper oxide on the surface of metallic copper
In the reaction,Mg + CuSO4 → MgSO4 + Cu :
Magnesium is displacing copper
Which oxidising agent will you use to oxidise hydrogen sulphide ?
Chlorine is often used as an oxidizing chemical to convert hydrogen sulfide gas to insoluble sulfur (a yellow solid).
An exothermic reaction is a chemical reaction that releases energy through light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy. Exothermic Reaction means "exo" meaning releases and "thermic" means heat.
Which metal fails to evolve hydrogen gas with dil. HCL ?
i) Aluminium metal will react with dilute hydrochloric acid to produce aqueous aluminium chloride, AlCl3 , and hydrogen gas, H2.
ii) The reaction between magnesium (Mg) and hydrochloric acid (HCl) combine to form a salt of magnesium chloride (MgCl) and release hydrogen gas (H2).This is a single replacement reaction.
iii) Copper is a very unreactive metal, and it does not react with hydrochloric acid. Hydrogen is above copper in a metal reactivity series, so copper cannot replace the hydrogen in HCl to form CuCl2
iv) Zinc reacts with hydrochloric acid to produce hydrogen gas because it's more reactive than hydrogen, and thus displaces the latter from an acid. By comparison