Initially Enable the I2C protocol feature in raspberry pi:

 1. sudo raspi-config
 2. Enable the I2C
 3. Reboot your system
 4. Connect the I2C device to its SDA and SCL pin respectively refer the pin out of raspberry pi.
 5. Meanwhile also add two line in the mention path :sudo nano /etc/modules
     -- # i2c-bcm2708 <Comment out>
     -- i2c-dev 
 6. Now cross check whether the correct connection are made or not
 7. Go to the terminal and type "sudo i2cdetect -y 1" it will list all the connected peripheral with raspberry pi
 8. If the address of the connected device is shown then initial validation is over.
 9. Further you can proceed with your program.