Explain the following:
An ore on treatment with dilute hydrochloric acid produces brisk effervescence .What type of ore is this? What steps will be required to obtain metal from the enriched ore?

Which of the following metals do not liberate hydrogen from dilute hydrochloric acid ?

Answer the following in one or two sentences What is concentration of ore?

Veena observes that during winter setting of milk into curd takes more time while during summer, the same process happens faster. She asks about this difference in time taken to her elder sister. She also asks her sister about why certain reactions occur rapidly while others occur slowly. Her sister explains her about the various factors that affect the rate of chemical reactions. Based on the above scenario, answer the following questions. The reaction of aluminum metal with dilute hydrochloric acid takes place faster as compared to zinc metal. What could be the reason for this difference?

What are the different steps involved in the manufacture of potassium dichomate from chromite ore?

Answer the given question : Name the two important stages in the process of obtaining metals from ores?

Solve the following examples/ numerical problems: A spherical lens is used to obtain an image on a screen . The size of the image is four times the size of the object. What is the type of lens and at what distance is the screen placed from the lens ?

Answer the following questions: What is bauxite? What are the main impurities found in this ore ?

Answer the following in one or two sentences In what form are ores/minerals genrally found in nature?

Answer the following questions: Show the steps involved in the extraction of moderately reactive metals from their sulphide ores .

Answer the following questions: What are the different methods used for removing gangue from ores ?