ACIDS , BASES AND SALTS

what happens when a solution of  an acid is mixed with a solution of a base in a test tube?a

• temperature of the solution increases 
• temperature of the solution decreases
• temperature remains constant
• no reaction

an aqueous soln turns red lithmus blue . excess addition of which of the following would reverse the change

• baking powder
• lime
• ammonium hydroxide solution
• HCL

calcium phosphate is present in tooth enamel its nature is

• basic
• acidic 
• neutral
• amphoteric

a sample of soil is mixed with water and allow to settle . The soln turns yellowish orange which of the foll soln will turn the colour to greenish blue 

• lemon juice
• vinegar
• common salt
• antacid

If a few drops of concentrated acid accidentally spills over the hand of a student,what should be done

• wash the hand with saline solution
• wash the hand immediately with plenty of water and apply a soln of sodium hydrogen carbonate
• after washing apply soln of sodium hydroxide
• neutralise the acid wih a strong alkali

common salt besides being used in kitchen can also be used as the raw material for making

• washing soda
• calcium salts
• plaster of paris
• slaked lime

To protect tooth decay we are advised to brush our teeth regurlarly.The toothpaste is

• acidic
• neutral
• basic
• corrosive

which of the foll phenomena occur when a small amunt of acid is added to water

• ionisation
• neutralisation
• dilution
• formation

which one of the foll can be used as acid-base indicator by  visually impared student 

• litmus
• turmeric
• vanilla essence
• petunia leaves

which of the foll substances will not give carbon dioxide on treatment with dilute acid

• marble
• limestone
• baking soda
• lime