Question Discussion & Solution

The Correct Answer is Ctrl + A.

 Key Points

• Ctrl + A Select all contents of the page in Microsoft Word.

 Additional Information

 Other shortcuts in Office

• Ctrl + B -- Bold highlighted selection.
• Ctrl + C -- Copy selected text.
• Ctrl + X -- Cut selected text.
• Ctrl + N -- Open new/blank document.
• Ctrl + O -- Open options.
• Ctrl + P -- Open the print window.
• Ctrl + F -- Open find box.
• Ctrl + I -- Italicise highlighted selection.
• Ctrl + K -- Insert link.
• Ctrl + U -- Underline highlighted selection.
• Ctrl + V -- Paste.
• Ctrl + Y -- Redo the last action performed.
• Ctrl + Z -- Undo last action.
• Ctrl + G -- Find and replace options.
• Ctrl + H -- Find and replace options.
• Ctrl + J -- Justify paragraph alignment.
• Ctrl + L -- Align selected text or line to the left.
• Ctrl + Q -- Align selected paragraph to the left.
• Ctrl + E -- Align selected text or line to the center.
• Ctrl + R -- Align selected text or line to the right.
• Ctrl + M -- Indent the paragraph.
• Ctrl + T -- Hanging indent.
• Ctrl + D -- Font options.
• Ctrl + Shift + F -- Change the font.

Pointers:

• Pointers in C language is a variable that stores/points to the address of another variable.
• A Pointer in C is used to allocate memory dynamically i.e. at run time.
• The pointer variable might belong to any of the data types such as int, float, char, double, short, etc.

Operators in pointers:

• * and & are the operators used in pointers.
• * gives us the value stored at a particular address whereas “ & “ gives us the address of the variable.

Hence, “49” should come next.

Battery and Engine are part of car but battery and engine are two different entity.

Therefore, above diagram best express relationship between Battery, Engine and Car.

The correct answer is Methane.

Key Points

• Methane (CH4)
  • It is the simplest hydrocarbon consisting of one carbon atom and four hydrogen atoms and the simplest hydrocarbon, is the most abundant hydrocarbon pollutant.
  • It is a powerful greenhouse gas.
  • Major natural sources of methane include emissions from wetlands, and oceans and from the digestive processes of termites.
  • Methane is more than 25 times as potent as carbon dioxide at trapping heat in the atmosphere.

Additional Information

• Butane is a gaseous component (at room temperature and atmospheric pressure) of the Alkane group having the chemical formula is C4H10.
• It is a colourless, highly flammable, and easily liquefied gas.
• In the abundance of oxygen, it forms Carbon dioxide, but if limited oxygen is available, then it forms Carbon Monoxide.

2C4H10 + 13O2 → 8CO2 + 10H2O                   (oxygen in plenty)

2C4H10 + 9O2 → 8CO + 10H2O                      (oxygen is limited)

• Uses –
  • Gasoline blending
  • Fuel gas
  • Fragrance extraction solvent
  • Feedstock for the manufacture of ethylene and butadiene
  • Ingredient for synthetic rubber
  • Isobutane to enhance the Octane number of gasoline in refineries.
• A propane molecule has three carbon atoms and eight hydrogen bonds and has the formula C3H8. 
• Propane is a colourless, easily liquefied, gaseous hydrocarbon (compound of carbon and hydrogen) and the third member of the paraffin series following methane and ethane.
• Propane is produced as a by-product of two other processes, natural gas processing and petroleum refining.
• It is separated in large quantities from natural gas, light crude oil, and oil-refinery gases and is commercially available as liquefied propane or as a major constituent of liquefied petroleum gas (LPG).
• Uses: 
  • It is used in LPG, also used as biofuel in buses and taxis and it is also the main gas in blowtorches and for hot air balloons.
  • Propane gas has become a popular choice for barbecues and portable stoves because its low boiling point makes it vaporize as soon as it is released from its pressurized container.
• The chemical formula of Ethane is C2H6.
• It is a colourless, odourless gas at normal temperature and pressure.
• It is extracted from natural gas on an industrial scale and is a petrochemical by-product of petroleum refining.
• Michael Faraday first synthesized it in 1834, using the electrolysis of a solution of potassium acetate.